#include <bits/stdc++.h>
using namespace std;
using ll = long long;
// const ll MOD = 1e9+7;

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n; cin >> n;
    vector<int> a(n+1), b(n+1), p(n+1, 0);
    for (int i = 1; i <= n; i++) {
    	cin >> a[i];
    }
    int B = 0;
    for (int i = 1; i <= n; i++) {
    	cin >> b[i];
    	B += b[i];
    	p[i] = p[i-1] + (b[i] - a[i]);
    	//cerr << p[i] << " ";
    }
    
    int res = B, mneddig = 0;
    for (int i = 1; i <= n; i++) {
    	mneddig = min(mneddig, p[i]);
    	res = min(res, B-(p[i]-mneddig));
    }
    cout << res << "\n";

    return 0;
}