using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vásárlás{
    class Program{
        static void Main(){
            int N = int.Parse(Console.ReadLine());
            int[] A = Console.ReadLine().Split().Select(int.Parse).ToArray(),
                  B = Console.ReadLine().Split().Select(int.Parse).ToArray(),
                  O = new int[N];

            int max = 0, maxi = -2, l = 0; 
            int mmax = 0, mmaxi = -1, lmax = 0;

            for(int i=0; i<N; i++){
                O[i] = B[i] - A[i];
                if(O[i] >= 0){
                    max += O[i];
                    //if( maxi == i) maxi = i;
                    l++;
                }else{
                    maxi = i + 1;
                    max = 0;
                    l = 0;
                }
                if (mmax < max){
                    mmax = max;
                    mmaxi = maxi; 
                    lmax = l;
                }
            }
            int o1 = 0;

            for(int i=0; i<N; i++){
                if (maxi <= i && i < maxi + lmax) o1 += A[i];
                else o1 += B[i];
            }

            /*for(int i=-1, to, j, k; i<N; i++){
                for(j=-1; j<N; j++){
                    to = 0;
                    for(k=0; k<N; k++){
                        if (i <= k && k <= j) to += A[k];
                        else to += B[k];
                    }
                    if (to < o1) o1 = to;
                }
            }*/
            Console.WriteLine(o1);
        }
    }
}