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