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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	}
} 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	}
} 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	} 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		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[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 for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		} {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		} int sum = 0; sum 0 for (int j = 0; j <= i; j++) {
				sum += a[j];
			} int j = 0; int j = 0; j 0 j <= i j i j++ j++ j {
				sum += a[j];
			} {
				sum += a[j];
			} sum += a[j] sum a[j] a j for (int j = i; j < n; j++) {
				sum += b[j];
			} int j = i; int j = i; j i j < n j n j++ j++ j {
				sum += b[j];
			} {
				sum += b[j];
			} sum += b[j] sum b[j] b j max = Math.max(max, sum) max Math.max(max, sum) Math.max Math max sum System.out.println(max) System.out.println System.out System System.out max sc.close() sc.close sc 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	}
} 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	}
} 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;
		for (int i = 0; i < n; i++) {
			int sum = 0;
			for (int j = 0; j <= i; j++) {
				sum += a[j];
			}
			for (int j = i; j < n; j++) {
				sum += b[j];
			}
			max = Math.max(max, sum);
		}

		System.out.println(max);
		sc.close();
	}
}
