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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        System.out.println(max);
    } main {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int[] a = new int[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        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[n]; a new int[n] n int[] b = new int[n]; b new int[n] n for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            a[i] = sc.nextInt();
        } {
            a[i] = sc.nextInt();
        } a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            b[i] = sc.nextInt();
        } {
            b[i] = sc.nextInt();
        } b[i] = sc.nextInt() b[i] b i sc.nextInt() sc.nextInt sc int max = 0; max 0 int total = 0; total 0 for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        } {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        } total += a[i] total a[i] a i int tmp = total; tmp total for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            } int j = n-1; int j = n-1; j n-1 n 1 j >= i j i j-- j-- j {
                tmp += b[j];
            } {
                tmp += b[j];
            } tmp += b[j] tmp b[j] b j max = Math.max(max, tmp) max Math.max(max, tmp) Math.max Math max tmp 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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        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[n];
        int[] b = new int[n];

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

        int max = 0;
        int total = 0;
        for (int i = 0; i < n; i++) {
            total += a[i];
            int tmp = total;
            for (int j = n-1; j >= i; j--) {
                tmp += b[j];
            }
            max = Math.max(max, tmp);
        }

        System.out.println(max);
    }
}
