import java.util.Scanner;

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

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        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[][] a = new int[2][n];
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = sc.nextInt();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        System.out.println(max);
    }
} Main public static void main(String[] args){
        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();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        System.out.println(max);
    } main {
        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();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        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[][] 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 int max = 0; max 0 int count = 0; count 0 for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        } int k = 0; int k = 0; k 0 k < n k n k++ k++ k {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        } {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        } for (int l = 0; l <= k; l++) {
                count += a[0][l];
            } int l = 0; int l = 0; l 0 l <= k l k l++ l++ l {
                count += a[0][l];
            } {
                count += a[0][l];
            } count += a[0][l] count a[0][l] a[0] a 0 l for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            } int m = n-1; int m = n-1; m n-1 n 1 m >= k m k m-- m-- m {
                count += a[1][m];
            } {
                count += a[1][m];
            } count += a[1][m] count a[1][m] a[1] a 1 m if (max < count) {
                max = count;
            } max < count max count {
                max = count;
            } max = count max count count = 0 count 0 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[][] a = new int[2][n];
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = sc.nextInt();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        System.out.println(max);
    }
} public class Main {
    public static void main(String[] args){
        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();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        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[][] a = new int[2][n];
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < n; j++) {
                a[i][j] = sc.nextInt();
            }
        }

        int max = 0;
        int count = 0;
        for (int k = 0; k < n; k++) {
            for (int l = 0; l <= k; l++) {
                count += a[0][l];
            }
            for (int m = n-1; m >= k; m--) {
                count += a[1][m];
            }
            if (max < count) {
                max = count;
            }
            count = 0;
        }

        System.out.println(max);
    }
}