import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();}
    private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}}        
    private static Scanner sc;

    private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
    public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();}
    private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}}        
    private static Scanner sc;

    private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    }
} Main private static Scanner sc; sc public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();} main {Main instance = new Main();sc = instance.new Scanner();instance.solve();} Main instance = new Main(); instance new Main() sc = instance.new Scanner() sc instance.new Scanner() instance instance instance.solve() instance.solve instance String[] args args private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    } solve {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    } int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] A1 = new int[N]; A1 new int[N] N int[] A2 = new int[N]; A2 new int[N] N for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            A1[i] = sc.nextInt();
        } {
            A1[i] = sc.nextInt();
        } A1[i] = sc.nextInt() A1[i] A1 i sc.nextInt() sc.nextInt sc for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            A2[i] = sc.nextInt();
        } {
            A2[i] = sc.nextInt();
        } A2[i] = sc.nextInt() A2[i] A2 i sc.nextInt() sc.nextInt sc int ans = 0; ans 0 for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        } {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        } int tmp = 0; tmp 0 for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            } int j = 0; int j = 0; j 0 j <= i j i j++ j++ j {
                tmp += A1[j];
            } {
                tmp += A1[j];
            } tmp += A1[j] tmp A1[j] A1 j for (int j = i; j < N; j++) {
                tmp += A2[j];
            } int j = i; int j = i; j i j < N j N j++ j++ j {
                tmp += A2[j];
            } {
                tmp += A2[j];
            } tmp += A2[j] tmp A2[j] A2 j if (tmp > ans) {
                ans = tmp;
            } tmp > ans tmp ans {
                ans = tmp;
            } ans = tmp ans tmp System.out.println(ans) System.out.println System.out System System.out ans private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}} Scanner String[] s = new String[0]; s new String[0] 0 String regex = " "; regex " " int i = 0; i 0 BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }} next {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }} try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; } catch (IOException e) { return null; } IOException e { return null; } return null; null {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} if (i < s.length) { return s[i++];} i < s.length i s.length s s.length { return s[i++];} return s[i++]; s[i++] s i++ i String st = br.readLine(); st br.readLine() br.readLine br while ("".equals(st)) { st = br.readLine(); } "".equals(st) "".equals "" st { st = br.readLine(); } st = br.readLine() st br.readLine() br.readLine br s = st.split(regex, 0) s st.split(regex, 0) st.split st regex 0 i = 0 i 0 return s[i++]; s[i++] s i++ i public int nextInt(){return Integer.parseInt(next());} nextInt {return Integer.parseInt(next());} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public class Main {
    public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();}
    private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}}        
    private static Scanner sc;

    private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();}
    private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}}        
    private static Scanner sc;

    private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) {Main instance = new Main();sc = instance.new Scanner();instance.solve();}
    private class Scanner {String[] s = new String[0];String regex = " ";int i = 0;BufferedReader br = new BufferedReader(new InputStreamReader(System.in));public String next() {try {if (i < s.length) { return s[i++];}String st = br.readLine();while ("".equals(st)) { st = br.readLine(); }s = st.split(regex, 0);i = 0;return s[i++];} catch (IOException e) { return null; }}public int nextInt(){return Integer.parseInt(next());}}        
    private static Scanner sc;

    private void solve() {
        int N = sc.nextInt();
        int[] A1 = new int[N];
        int[] A2 = new int[N];
        for (int i = 0; i < N; i++) {
            A1[i] = sc.nextInt();
        }
        for (int i = 0; i < N; i++) {
            A2[i] = sc.nextInt();
        }
        int ans = 0;
        for (int i = 0; i < N; i++) {
            int tmp = 0;
            for (int j = 0; j <= i; j++) {
                tmp += A1[j];
            }
            for (int j = i; j < N; j++) {
                tmp += A2[j];
            }
            if (tmp > ans) {
                ans = tmp;
            }
        }
        System.out.println(ans);
    }
}