import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.NoSuchElementException;
import java.util.Queue;


public class Main {
	public static void main(String[] args) {


		slover();
		out.flush();
	}
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//StringBuffer S = new StringBuffer(sc.next());
		//String hoge2 = str.reverse().toString();
		//map.containsKey(A)
		//Map<Integer, Integer> map = new HashMap<Integer, Integer>(N);
		/*for ( キーのデータ型 key : マップの名前.keySet() ) {
			データのデータ型 data = マップの名前.get( key );
	 
			// keyやdataを使った処理;
		}*/
		//int i = Integer.parseInt(s);
		//Queue<String> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		//Deque<String> dd=new ArrayDeque<>();//push後ろに入れる,poll(pop)後ろからとる,peek addは先頭に入るからバグ注意
		//stackdfsは後ろから実行される
		//ArrayList<Integer> cc = new ArrayList<>(N);
		//cc.contains(tmp)
		//Arrays.asList(c).contains("a")
		//list.set(1,"walk");//1 1 2 3 5
	 
	 
		private static int INF =1000000007;
	 
		
		private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		}
		
		
	private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	}






	
	static void p(String ans) {out.println(ans);};
	static void p(int ans) {out.println(ans);};
	static void p() {out.println();};
	static void p(long ans) {out.println(ans);};
	static void p(double ans) {out.println(ans);};

	static void pn(String ans) {out.print(ans);};
	static void pn(int ans) {out.print(ans);};
	static void pn() {out.print("");};
	static void pn(long ans) {out.print(ans);};
	static void pn(double ans) {out.print(ans);};

	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  }
}
 import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.ArrayDeque; ArrayDeque java.util import java.util.NoSuchElementException; NoSuchElementException java.util import java.util.Queue; Queue java.util public class Main {
	public static void main(String[] args) {


		slover();
		out.flush();
	}
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//StringBuffer S = new StringBuffer(sc.next());
		//String hoge2 = str.reverse().toString();
		//map.containsKey(A)
		//Map<Integer, Integer> map = new HashMap<Integer, Integer>(N);
		/*for ( キーのデータ型 key : マップの名前.keySet() ) {
			データのデータ型 data = マップの名前.get( key );
	 
			// keyやdataを使った処理;
		}*/
		//int i = Integer.parseInt(s);
		//Queue<String> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		//Deque<String> dd=new ArrayDeque<>();//push後ろに入れる,poll(pop)後ろからとる,peek addは先頭に入るからバグ注意
		//stackdfsは後ろから実行される
		//ArrayList<Integer> cc = new ArrayList<>(N);
		//cc.contains(tmp)
		//Arrays.asList(c).contains("a")
		//list.set(1,"walk");//1 1 2 3 5
	 
	 
		private static int INF =1000000007;
	 
		
		private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		}
		
		
	private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	}






	
	static void p(String ans) {out.println(ans);};
	static void p(int ans) {out.println(ans);};
	static void p() {out.println();};
	static void p(long ans) {out.println(ans);};
	static void p(double ans) {out.println(ans);};

	static void pn(String ans) {out.print(ans);};
	static void pn(int ans) {out.print(ans);};
	static void pn() {out.print("");};
	static void pn(long ans) {out.print(ans);};
	static void pn(double ans) {out.print(ans);};

	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  }
} Main static FastScanner sc = new FastScanner(); sc new FastScanner() static PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) private static int INF =1000000007; INF 1000000007 public static void main(String[] args) {


		slover();
		out.flush();
	} main {


		slover();
		out.flush();
	} slover() slover out.flush() out.flush out String[] args args private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	} slover {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	} int N=sc.nextInt(); N sc.nextInt() sc.nextInt sc int a[][]=new int[N][2]; a new int[N][2] N 2 for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		} int k=0; int k=0; k 0 k<2 k 2 k++ k++ k {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		} {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		} for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			} int i=0; int i=0; i 0 i<N i N i++ i++ i {
				a[i][k]=sc.nextInt();
			} {
				a[i][k]=sc.nextInt();
			} a[i][k]=sc.nextInt() a[i][k] a[i] a i k sc.nextInt() sc.nextInt sc Queue<D> qq=new ArrayDeque<>(); qq new ArrayDeque<>() qq.add(new D(0,0,0)) qq.add qq new D(0,0,0) int ans=0; ans 0 while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		} !qq.isEmpty() qq.isEmpty() qq.isEmpty qq {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		} D cur=qq.poll(); cur qq.poll() qq.poll qq if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			} cur.k==1&&cur.i==N-1 cur.k==1 cur.k cur cur.k 1 cur.i==N-1 cur.i cur cur.i N-1 N 1 {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			} ans=Math.max(ans, cur.s+a[cur.i][cur.k]) ans Math.max(ans, cur.s+a[cur.i][cur.k]) Math.max Math ans cur.s+a[cur.i][cur.k] cur.s cur cur.s a[cur.i][cur.k] a[cur.i] a cur.i cur cur.i cur.k cur cur.k continue; if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			} cur.k==0&&cur.i==N-1 cur.k==0 cur.k cur cur.k 0 cur.i==N-1 cur.i cur cur.i N-1 N 1 {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			} qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k])) qq.add qq new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]) if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			} cur.k==0 cur.k cur cur.k 0 {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			} qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k])) qq.add qq new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]) qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k])) qq.add qq new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			} qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k])) qq.add qq new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]) p(ans) p ans return 0; 0 static void p(String ans) {out.println(ans);} p {out.println(ans);} out.println(ans) out.println out ans String ans ans static void p(int ans) {out.println(ans);} p {out.println(ans);} out.println(ans) out.println out ans int ans ans static void p() {out.println();} p {out.println();} out.println() out.println out static void p(long ans) {out.println(ans);} p {out.println(ans);} out.println(ans) out.println out ans long ans ans static void p(double ans) {out.println(ans);} p {out.println(ans);} out.println(ans) out.println out ans double ans ans static void pn(String ans) {out.print(ans);} pn {out.print(ans);} out.print(ans) out.print out ans String ans ans static void pn(int ans) {out.print(ans);} pn {out.print(ans);} out.print(ans) out.print out ans int ans ans static void pn() {out.print("");} pn {out.print("");} out.print("") out.print out "" static void pn(long ans) {out.print(ans);} pn {out.print(ans);} out.print(ans) out.print out ans long ans ans static void pn(double ans) {out.print(ans);} pn {out.print(ans);} out.print(ans) out.print out ans double ans ans private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		} D int k k i i s; s D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			} D {
				this.k=k;
				this.i=i;
				this.s=s;
			} this.k=k this.k this this.k k this.i=i this.i this this.i i this.s=s this.s this this.s s int k k int i i int s s static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  } FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    } hasNextByte {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    } if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      } ptr < buflen ptr buflen {
	        return true;
	      } return true; true {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      } ptr = 0 ptr 0 try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        } catch (IOException e) {
	          e.printStackTrace();
	        } IOException e {
	          e.printStackTrace();
	        } e.printStackTrace() e.printStackTrace e {
	          buflen = in.read(buffer);
	        } buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
	          return false;
	        } buflen <= 0 buflen 0 {
	          return false;
	        } return false; false return true; true private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    } readByte {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    } if (hasNextByte()) return buffer[ptr++];
	      else return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    } isPrintableChar {
	      return 33 <= c && c <= 126;
	    } return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    } skipUnprintable {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    } while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    } hasNext {
	      skipUnprintable();
	      return hasNextByte();
	    } skipUnprintable() skipUnprintable return hasNextByte(); hasNextByte() hasNextByte public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    } next {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      } isPrintableChar(b) isPrintableChar b {
	        sb.appendCodePoint(b);
	        b = readByte();
	      } sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    } nextLong {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
	        minus = true;
	        b = readByte();
	      } b == '-' b '-' {
	        minus = true;
	        b = readByte();
	      } minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      } b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
	        throw new NumberFormatException();
	      } throw new NumberFormatException(); new NumberFormatException() while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      } true {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      } if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        } '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
	          n *= 10;
	          n += b - '0';
	        } n *= 10 n 10 n += b - '0' n b - '0' b '0' if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        } b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
	          return minus ? -n : n;
	        } return minus ? -n : n; minus ? -n : n minus -n n n {
	          throw new NumberFormatException();
	        } throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public int nextInt() {
	      return (int) nextLong();
	    } nextInt {
	      return (int) nextLong();
	    } return (int) nextLong(); (int) nextLong() nextLong public double nextDouble(){
	    	return Double.parseDouble(next());
	    } nextDouble {
	    	return Double.parseDouble(next());
	    } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    } nextIntArray {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    } if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } oneBased {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } int[] array = new int[N + 1]; array new int[N + 1] N + 1 N 1 for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        } int i = 1; int i = 1; i 1 i <= N i N i++ i++ i {
	          array[i] = sc.nextInt();
	        } {
	          array[i] = sc.nextInt();
	        } array[i] = sc.nextInt() array[i] array i sc.nextInt() sc.nextInt sc return array; array {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } int[] array = new int[N]; array new int[N] N for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
	          array[i] = sc.nextInt();
	        } {
	          array[i] = sc.nextInt();
	        } array[i] = sc.nextInt() array[i] array i sc.nextInt() sc.nextInt sc return array; array int N N boolean oneBased oneBased public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    } nextLongArray {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    } if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } oneBased {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } long[] array = new long[N + 1]; array new long[N + 1] N + 1 N 1 for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        } int i = 1; int i = 1; i 1 i <= N i N i++ i++ i {
	          array[i] = sc.nextLong();
	        } {
	          array[i] = sc.nextLong();
	        } array[i] = sc.nextLong() array[i] array i sc.nextLong() sc.nextLong sc return array; array {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } long[] array = new long[N]; array new long[N] N for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
	          array[i] = sc.nextLong();
	        } {
	          array[i] = sc.nextLong();
	        } array[i] = sc.nextLong() array[i] array i sc.nextLong() sc.nextLong sc return array; array int N N boolean oneBased oneBased public class Main {
	public static void main(String[] args) {


		slover();
		out.flush();
	}
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//StringBuffer S = new StringBuffer(sc.next());
		//String hoge2 = str.reverse().toString();
		//map.containsKey(A)
		//Map<Integer, Integer> map = new HashMap<Integer, Integer>(N);
		/*for ( キーのデータ型 key : マップの名前.keySet() ) {
			データのデータ型 data = マップの名前.get( key );
	 
			// keyやdataを使った処理;
		}*/
		//int i = Integer.parseInt(s);
		//Queue<String> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		//Deque<String> dd=new ArrayDeque<>();//push後ろに入れる,poll(pop)後ろからとる,peek addは先頭に入るからバグ注意
		//stackdfsは後ろから実行される
		//ArrayList<Integer> cc = new ArrayList<>(N);
		//cc.contains(tmp)
		//Arrays.asList(c).contains("a")
		//list.set(1,"walk");//1 1 2 3 5
	 
	 
		private static int INF =1000000007;
	 
		
		private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		}
		
		
	private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	}






	
	static void p(String ans) {out.println(ans);};
	static void p(int ans) {out.println(ans);};
	static void p() {out.println();};
	static void p(long ans) {out.println(ans);};
	static void p(double ans) {out.println(ans);};

	static void pn(String ans) {out.print(ans);};
	static void pn(int ans) {out.print(ans);};
	static void pn() {out.print("");};
	static void pn(long ans) {out.print(ans);};
	static void pn(double ans) {out.print(ans);};

	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  }
} public class Main {
	public static void main(String[] args) {


		slover();
		out.flush();
	}
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//StringBuffer S = new StringBuffer(sc.next());
		//String hoge2 = str.reverse().toString();
		//map.containsKey(A)
		//Map<Integer, Integer> map = new HashMap<Integer, Integer>(N);
		/*for ( キーのデータ型 key : マップの名前.keySet() ) {
			データのデータ型 data = マップの名前.get( key );
	 
			// keyやdataを使った処理;
		}*/
		//int i = Integer.parseInt(s);
		//Queue<String> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		//Deque<String> dd=new ArrayDeque<>();//push後ろに入れる,poll(pop)後ろからとる,peek addは先頭に入るからバグ注意
		//stackdfsは後ろから実行される
		//ArrayList<Integer> cc = new ArrayList<>(N);
		//cc.contains(tmp)
		//Arrays.asList(c).contains("a")
		//list.set(1,"walk");//1 1 2 3 5
	 
	 
		private static int INF =1000000007;
	 
		
		private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		}
		
		
	private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	}






	
	static void p(String ans) {out.println(ans);};
	static void p(int ans) {out.println(ans);};
	static void p() {out.println();};
	static void p(long ans) {out.println(ans);};
	static void p(double ans) {out.println(ans);};

	static void pn(String ans) {out.print(ans);};
	static void pn(int ans) {out.print(ans);};
	static void pn() {out.print("");};
	static void pn(long ans) {out.print(ans);};
	static void pn(double ans) {out.print(ans);};

	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  }
} Main
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.NoSuchElementException;
import java.util.Queue;


public class Main {
	public static void main(String[] args) {


		slover();
		out.flush();
	}
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//StringBuffer S = new StringBuffer(sc.next());
		//String hoge2 = str.reverse().toString();
		//map.containsKey(A)
		//Map<Integer, Integer> map = new HashMap<Integer, Integer>(N);
		/*for ( キーのデータ型 key : マップの名前.keySet() ) {
			データのデータ型 data = マップの名前.get( key );
	 
			// keyやdataを使った処理;
		}*/
		//int i = Integer.parseInt(s);
		//Queue<String> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		//Deque<String> dd=new ArrayDeque<>();//push後ろに入れる,poll(pop)後ろからとる,peek addは先頭に入るからバグ注意
		//stackdfsは後ろから実行される
		//ArrayList<Integer> cc = new ArrayList<>(N);
		//cc.contains(tmp)
		//Arrays.asList(c).contains("a")
		//list.set(1,"walk");//1 1 2 3 5
	 
	 
		private static int INF =1000000007;
	 
		
		private static class D{
			int k,i,s;
			D(int k,int i,int s){
				this.k=k;
				this.i=i;
				this.s=s;
			}
			
		}
		
		
	private static int slover() {
		int N=sc.nextInt();
		
		int a[][]=new int[N][2];
		
		for(int k=0;k<2;k++) {
			for(int i=0;i<N;i++) {
				a[i][k]=sc.nextInt();
			}
		}
		
		Queue<D> qq=new ArrayDeque<>(); //add,poll,peek BFSは前から実行される
		qq.add(new D(0,0,0));
		int ans=0;
		while(!qq.isEmpty()) {
			D cur=qq.poll();
			if(cur.k==1&&cur.i==N-1) {
			ans=Math.max(ans, cur.s+a[cur.i][cur.k]);
			continue;
			}
			if(cur.k==0&&cur.i==N-1) {
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
			}
			else if(cur.k==0) {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
				qq.add(new D(cur.k+1,cur.i,cur.s+a[cur.i][cur.k]));
				
			}else {
				qq.add(new D(cur.k,cur.i+1,cur.s+a[cur.i][cur.k]));
			}
			
		}
		p(ans);
		return 0;
	}






	
	static void p(String ans) {out.println(ans);};
	static void p(int ans) {out.println(ans);};
	static void p() {out.println();};
	static void p(long ans) {out.println(ans);};
	static void p(double ans) {out.println(ans);};

	static void pn(String ans) {out.print(ans);};
	static void pn(int ans) {out.print(ans);};
	static void pn() {out.print("");};
	static void pn(long ans) {out.print(ans);};
	static void pn(double ans) {out.print(ans);};

	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;

	    private boolean hasNextByte() {
	      if (ptr < buflen) {
	        return true;
	      } else {
	        ptr = 0;
	        try {
	          buflen = in.read(buffer);
	        } catch (IOException e) {
	          e.printStackTrace();
	        }
	        if (buflen <= 0) {
	          return false;
	        }
	      }
	      return true;
	    }

	    private int readByte() {
	      if (hasNextByte()) return buffer[ptr++];
	      else return -1;
	    }

	    private static boolean isPrintableChar(int c) {
	      return 33 <= c && c <= 126;
	    }

	    private void skipUnprintable() {
	      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
	    }

	    public boolean hasNext() {
	      skipUnprintable();
	      return hasNextByte();
	    }

	    public String next() {
	      if (!hasNext()) throw new NoSuchElementException();
	      StringBuilder sb = new StringBuilder();
	      int b = readByte();
	      while (isPrintableChar(b)) {
	        sb.appendCodePoint(b);
	        b = readByte();
	      }
	      return sb.toString();
	    }

	    public long nextLong() {
	      if (!hasNext()) throw new NoSuchElementException();
	      long n = 0;
	      boolean minus = false;
	      int b = readByte();
	      if (b == '-') {
	        minus = true;
	        b = readByte();
	      }
	      if (b < '0' || '9' < b) {
	        throw new NumberFormatException();
	      }
	      while (true) {
	        if ('0' <= b && b <= '9') {
	          n *= 10;
	          n += b - '0';
	        } else if (b == -1 || !isPrintableChar(b)) {
	          return minus ? -n : n;
	        } else {
	          throw new NumberFormatException();
	        }
	        b = readByte();
	      }
	    }

	    public int nextInt() {
	      return (int) nextLong();
	    }

	    public double nextDouble(){
	    	return Double.parseDouble(next());
	    }

	    public int[] nextIntArray(int N, boolean oneBased) {
	      if (oneBased) {
	        int[] array = new int[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      } else {
	        int[] array = new int[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextInt();
	        }
	        return array;
	      }
	    }

	    public long[] nextLongArray(int N, boolean oneBased) {
	      if (oneBased) {
	        long[] array = new long[N + 1];
	        for (int i = 1; i <= N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      } else {
	        long[] array = new long[N];
	        for (int i = 0; i < N; i++) {
	          array[i] = sc.nextLong();
	        }
	        return array;
	      }
	    }
	  }
}

