import java.util.*;

public class Main {

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

        int n = sc.nextInt();
        int[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

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

} 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[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

        int max = 0;
        for (int i = 0; i < n; i++) {
            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[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[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

        int max = 0;
        for (int i = 0; i < n; i++) {
            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            }
            max = Math.max(max, sum);
        }
        System.out.println(max);
    } main {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

        int max = 0;
        for (int i = 0; i < n; i++) {
            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[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[] lineOne = new int[n]; lineOne new int[n] n int[] lineTwo = new int[n]; lineTwo new int[n] n for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            lineOne[i] = sc.nextInt();
        } {
            lineOne[i] = sc.nextInt();
        } lineOne[i] = sc.nextInt() lineOne[i] lineOne i sc.nextInt() sc.nextInt sc for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            lineTwo[i] = sc.nextInt();
        } {
            lineTwo[i] = sc.nextInt();
        } lineTwo[i] = sc.nextInt() lineTwo[i] lineTwo 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 (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[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 (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            }
            max = Math.max(max, sum);
        } {
            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            }
            max = Math.max(max, sum);
        } int sum = 0; sum 0 for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            } int j = 0; int j = 0; j 0 j < n j n j++ j++ j {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            } {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[j];
                }
            } if (j <= i) {
                    sum += lineOne[j];
                } j <= i j i {
                    sum += lineOne[j];
                } sum += lineOne[j] sum lineOne[j] lineOne j if (j >= i) {
                    sum += lineTwo[j];
                } j >= i j i {
                    sum += lineTwo[j];
                } sum += lineTwo[j] sum lineTwo[j] lineTwo 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[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

        int max = 0;
        for (int i = 0; i < n; i++) {
            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (j <= i) {
                    sum += lineOne[j];
                }
                if (j >= i) {
                    sum += lineTwo[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[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

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

} Main
import java.util.*;

public class Main {

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

        int n = sc.nextInt();
        int[] lineOne = new int[n];
        int[] lineTwo = new int[n];

        for (int i = 0; i < n; i++) {
            lineOne[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            lineTwo[i] = sc.nextInt();
        }

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

}