import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	} 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 < N; i++) {
			a[0][i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			a[0][i] = sc.nextInt();
		} {
			a[0][i] = sc.nextInt();
		} a[0][i] = sc.nextInt() a[0][i] a[0] a 0 i sc.nextInt() sc.nextInt sc for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			a[1][i] = sc.nextInt();
		} {
			a[1][i] = sc.nextInt();
		} a[1][i] = sc.nextInt() a[1][i] a[1] a 1 i sc.nextInt() sc.nextInt sc int x = 0; x 0 int ans = 0; ans 0 for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		} {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		} x = 0 x 0 for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			} int j = 0; int j = 0; j 0 j < N j N j++ j++ j {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			} {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			} if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				} j < i j i {
					x += a[0][j];
				} x += a[0][j] x a[0][j] a[0] a 0 j if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				} j == i j i {
					x += a[0][j];
					x += a[1][j];
				} x += a[0][j] x a[0][j] a[0] a 0 j x += a[1][j] x a[1][j] a[1] a 1 j {
					x += a[1][j];
				} x += a[1][j] x a[1][j] a[1] a 1 j if (ans < x) {
				ans = x;
			} ans < x ans x {
				ans = x;
			} ans = x ans x System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		// 要素の入力、格納
		int N = sc.nextInt();
		int a[][] = new int[2][N];
		for (int i = 0; i < N; i++) {
			a[0][i] = sc.nextInt();
		}
		for (int i = 0; i < N; i++) {
			a[1][i] = sc.nextInt();
		}
		int x = 0;
		int ans = 0;

		for (int i = 0; i < N; i++) {
			x = 0;
			for (int j = 0; j < N; j++) {
				if (j < i) {
					x += a[0][j];
				} else if (j == i) {
					x += a[0][j];
					x += a[1][j];
				} else {
					x += a[1][j];
				}
			}
			if (ans < x) {
				ans = x;
			}
		}

		// 出力
		System.out.println(ans);
	}
}
