import java.util.Scanner;

public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  }
}     import java.util.Scanner; Scanner java.util public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  } main {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] A1 = new int[N]; A1 new int[N] N int[] A2 = new int[N]; A2 new int[N] N for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    } int i =0; int i =0; i 0 i<N i N i++ i++ i {
      A1[i] = sc.nextInt();
    } {
      A1[i] = sc.nextInt();
    } A1[i] = sc.nextInt() A1[i] A1 i sc.nextInt() sc.nextInt sc for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    } int i =0; int i =0; i 0 i<N i N i++ i++ i {
      A2[i] = sc.nextInt();
    } {
      A2[i] = sc.nextInt();
    } A2[i] = sc.nextInt() A2[i] A2 i sc.nextInt() sc.nextInt sc int max =0; max 0 for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    } int k =0; int k =0; k 0 k<N k N k++ k++ k { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    } { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    } int ans =0; ans 0 for (int i =k; i<N; i++) {
        ans += A2[i];
      } int i =k; int i =k; i k i<N i N i++ i++ i {
        ans += A2[i];
      } {
        ans += A2[i];
      } ans += A2[i] ans A2[i] A2 i for (int j =0; j<=k; j++) {
        ans += A1[j];
      } int j =0; int j =0; j 0 j<=k j k j++ j++ j {
        ans += A1[j];
      } {
        ans += A1[j];
      } ans += A1[j] ans A1[j] A1 j max = Math.max(ans,max) max Math.max(ans,max) Math.max Math ans max System.out.println(max) System.out.println System.out System System.out max String[] args args public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  }
} public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  }
} Main
import java.util.Scanner;

public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] A1 = new int[N];
    int[] A2 = new int[N];
    for (int i =0; i<N; i++) {
      A1[i] = sc.nextInt();
    }
    for (int i =0; i<N; i++) {
      A2[i] = sc.nextInt();
    }
    int max =0;
    for (int k =0; k<N; k++) { //2行目に行くタイミング
      int ans =0;
      for (int i =k; i<N; i++) {
        ans += A2[i];
      }
      for (int j =0; j<=k; j++) {
        ans += A1[j];
      }
      max = Math.max(ans,max);
    }
    System.out.println(max);  
  }
}    