// Created by Armin on 2/1/2025.

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pp = pair<int, int>;

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);
    
    int n; cin >> n;
    vector<int> a(n), b(n);
    int sumb = 0;
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    }
    vector<int> ba(n);
    for (int i = 0; i < n; i++) {
      cin >> b[i];
      sumb += b[i];
      ba[i] = b[i] - a[i];
    }

    int i = 0, j = 0, sum = 0;
    while (i + 1 < n && j + 1 < n) {
      if (sum + ba[j] < 0) {
        j++;
        i = j;
        sum = ba[i];
      } else {
        sum += ba[j];
        j++;
      }
    }
    int d = 0, c = 0;
    for (int k = i; k <= j; k++) {
      d += a[k];
      c += b[k];
    }
    cout << sumb - c + d << '\n';
    
    return 0;
}