import 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    }
} import java.util.*; util.* java 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    }
} 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] a = new int[n];
        int[] b = new int[n];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    } 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 int sumA = 0; sumA 0 int sumB = 0; sumB 0 for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            a[i] = sc.nextInt();
            sumA += a[i];
        } {
            a[i] = sc.nextInt();
            sumA += a[i];
        } a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc sumA += a[i] sumA a[i] a i for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            b[i] = sc.nextInt();
            sumB += b[i];
        } {
            b[i] = sc.nextInt();
            sumB += b[i];
        } b[i] = sc.nextInt() b[i] b i sc.nextInt() sc.nextInt sc sumB += b[i] sumB b[i] b i int[] ans = new int[n]; ans new int[n] n ans[0] = sumB + a[0] ans[0] ans 0 sumB + a[0] sumB a[0] a 0 for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        } int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        } {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        } ans[i] = ans[i - 1] - b[i - 1] + a[i] ans[i] ans i ans[i - 1] - b[i - 1] + a[i] ans[i - 1] - b[i - 1] ans[i - 1] ans i - 1 i 1 b[i - 1] b i - 1 i 1 a[i] a i Arrays.sort(ans) Arrays.sort Arrays ans System.out.println(ans[n - 1]) System.out.println System.out System System.out ans[n - 1] ans n - 1 n 1 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    }
} 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    }
} Main
import 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];
        int sumA = 0;
        int sumB = 0;
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
            sumA += a[i];
        }
        for (int i = 0; i < n; i++) {
            b[i] = sc.nextInt();
            sumB += b[i];
        }
        int[] ans = new int[n];
        ans[0] = sumB + a[0];
        for (int i = 1; i < n; i++) {
            ans[i] = ans[i - 1] - b[i - 1] + a[i];
        }
        Arrays.sort(ans);
        System.out.println(ans[n - 1]);
    }
}
