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[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	}

} 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[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[][] a = new int[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	} main {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[][] a = new int[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	} 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[3][n+1]; a new int[3][n+1] 3 n+1 n 1 for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		} int i=1; int i=1; i 1 i<=2 i 2 i++ i++ i {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		} {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		} for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			} int j=1; int j=1; j 1 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 sc.close() sc.close sc int dmax = 0; dmax 0 int aup = 0; aup 0 int adown = 0; adown 0 for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		} int k=1; int k=1; k 1 k<=n k n k++ k++ k {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		} {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		} for (int i=1; i<=k; i++) {
					aup += a[1][i];
			} int i=1; int i=1; i 1 i<=k i k i++ i++ i {
					aup += a[1][i];
			} {
					aup += a[1][i];
			} aup += a[1][i] aup a[1][i] a[1] a 1 i for (int i=k; i<=n; i++) {
				adown += a[2][i];
			} int i=k; int i=k; i k i<=n i n i++ i++ i {
				adown += a[2][i];
			} {
				adown += a[2][i];
			} adown += a[2][i] adown a[2][i] a[2] a 2 i dmax = Math.max(dmax, aup+adown) dmax Math.max(dmax, aup+adown) Math.max Math dmax aup+adown aup adown aup = 0 aup 0 adown = 0 adown 0 System.out.println(dmax) System.out.println System.out System System.out dmax 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[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[][] a = new int[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	}

} 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[3][n+1];
		for (int i=1; i<=2; i++) {
			for (int j=1; j<=n; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		sc.close();
		int dmax = 0;
		int aup = 0;
		int adown = 0;
		for (int k=1; k<=n; k++) {
			for (int i=1; i<=k; i++) {
					aup += a[1][i];
			}
			for (int i=k; i<=n; i++) {
				adown += a[2][i];
			}
			dmax = Math.max(dmax, aup+adown);
			aup = 0;
			adown = 0;
		}
		System.out.println(dmax);
	}

}