import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    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 max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    System.out.println(max);
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    System.out.println(max);
  } main {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    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 max = 0; max 0 int[][] a = new int[2][n]; a new int[2][n] 2 n for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    } int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    } {
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    } for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      } int j = 0; int j = 0; j 0 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 for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    } {
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    } int count = 0; count 0 for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      } int j = 0; int j = 0; j 0 j < n j n j ++ j ++ j {
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      } {
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      } if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        } i == j i j {
          count += a[0][j] + a[1][j];
        } count += a[0][j] + a[1][j] count a[0][j] + a[1][j] a[0][j] a[0] a 0 j a[1][j] a[1] a 1 j if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        } i > j i j {
          count += a[0][j];
        } count += a[0][j] count a[0][j] a[0] a 0 j {
          count += a[1][j];
        } count += a[1][j] count a[1][j] a[1] a 1 j max = Math.max(max, count) max Math.max(max, count) Math.max Math max count 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 max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    System.out.println(max);
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    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 max = 0;
    int[][] a = new int[2][n];
    for(int i = 0; i < 2; i++){
      for(int j = 0; j < n; j++){
        a[i][j] = sc.nextInt();
      }
    }
    for(int i = 0; i < n; i++){
      int count = 0;
      for(int j = 0; j < n; j ++){
        if(i == j){
          count += a[0][j] + a[1][j];
        }else if(i > j){
          count += a[0][j];
        }else{
          count += a[1][j];
        }
      }
      max = Math.max(max, count);
    }
    System.out.println(max);
  }
}