import java.util.Arrays;
import java.util.Scanner;

public class Main {
	int sum = 0;
	int max = 0;
	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().run();
	}
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
	int sum = 0;
	int max = 0;
	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().run();
	}
} Main int sum = 0; sum 0 int max = 0; max 0 void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	} run {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[][] A = new int[2][N]; A new int[2][N] 2 N for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		} int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		} {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		} for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			} int j = 0; int j = 0; j 0 j < N j N j++ j++ j {
				A[i][j] = sc.nextInt();
			} {
				A[i][j] = sc.nextInt();
			} A[i][j] = sc.nextInt() A[i][j] A[i] A i j sc.nextInt() sc.nextInt sc for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		} {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		} for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			} int j = 0; int j = 0; j 0 j < N j N j++ j++ j {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			} {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			} if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j]; j<i j i sum += A[0][j] sum A[0][j] A[0] A 0 j if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j]; i == j i j sum += A[0][j] + A[1][j] sum A[0][j] + A[1][j] A[0][j] A[0] A 0 j A[1][j] A[1] A 1 j sum += A[1][j] sum A[1][j] A[1] A 1 j if(sum > max) max = sum; sum > max sum max max = sum max sum sum = 0 sum 0 System.out.println(max) System.out.println System.out System System.out max sc.close() sc.close sc void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	} debug {
		System.out.println(Arrays.deepToString(o));
	} System.out.println(Arrays.deepToString(o)) System.out.println System.out System System.out Arrays.deepToString(o) Arrays.deepToString Arrays o Object... o o public static void main(String[] args) {
		new Main().run();
	} main {
		new Main().run();
	} new Main().run() new Main().run new Main() String[] args args public class Main {
	int sum = 0;
	int max = 0;
	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().run();
	}
} public class Main {
	int sum = 0;
	int max = 0;
	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().run();
	}
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	int sum = 0;
	int max = 0;
	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[][] A = new int[2][N];
		for(int i = 0; i < 2; i++) {
			for(int j = 0; j < N; j++) {
				A[i][j] = sc.nextInt();
			}
		}
		for(int i = 0; i < N; i++) {
			for(int j = 0; j < N; j++) {
				if(j<i) sum += A[0][j];
				else if(i == j) sum += A[0][j] + A[1][j];
				else sum += A[1][j];
			}
			if(sum > max) max = sum;
			sum = 0;
		}
		System.out.println(max);
		sc.close();
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().run();
	}
}