#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <deque>
#include <cmath>
#include <climits>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <functional>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <chrono>
#include <random>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define rep(a,b) for(int a = 0;a<b;a++)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(),a.end()
const int inf = 1e9;
const ll infl = 1e18;
const ll ize = 500007;
ll tr[ize*2];
void add(ll p, ll v)
{
p += ize;
tr[p] = v;
p /= 2;
while(p > 0)
{
tr[p] = max(tr[p*2], tr[p*2+1]);
p /= 2;
}
}
ll check(ll l, ll r)
{
l += ize;
r += ize;
ll ans = tr[l];
if(l != r) ans = max(ans, tr[r]);
while(l/2 != r/2)
{
if(l%2==0) ans = max(ans, tr[l+1]);
if(r%2==1) ans = max(ans, tr[r-1]);
l /= 2; r /= 2;
}
return ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
rep(i, ize*2) tr[i] = -infl;
int n;
cin >> n;
vector<ll> a(2*n);
vector<ll> b(2*n);
rep(i, n){
cin >> a[i];
a[i+n] = a[i];
}
rep(i, n){
cin >> b[i];
b[i+n] = b[i];
}
vector<ll> pref(2*n+1, 0);
rep(i, 2 * n){
pref[i+1] = pref[i] + b[i];
}
rep(i, 2*n){
add(i, a[i] - pref[i]);
}
ll w = infl;
rep(i, n){
ll x = check(i, i + n - 1) + pref[i];
w = min(w, x);
}
cout << max(0LL, w) << "\n";
return 0;
}
