#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for (auto i=(a); i<(b); ++i)
#define iter(it,c) for (auto it = (c).begin(); it != (c).end(); ++it)
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
const int INF = 2147483647;
const ll DINF = 9000000000000000000;

map<ii,ll> mem;

int n;
vector<ll> arr, sm;
ll tot = 0;
ll mn(int l, int r) {
    if ((r+1)%n == l) {
        return 0;
    }
    ii st(l, r);
    if (mem.find(st) != mem.end()) {
        return mem[st];
    }
    ll now = sm[r];
    if (l-1 >= 0) {
        now -= sm[l-1];
    }
    if (now < 0) {
        now += tot;
    }
    ll res = DINF;
    int li = l == 0 ? n-1 : l-1,
        ri = r == n-1 ? 0 : r+1;
    res = min(res, max(arr[li]-now, mn(li, r)));
    res = min(res, max(arr[ri]-now, mn(l, ri)));
    return mem[st] = res;
}

int main() {
    cin >> n;
    arr = vector<ll>(n);
    sm = vector<ll>(n);
    rep(i,0,n) {
        cin >> arr[i];
        sm[i] = arr[i];
        if (i-1 >= 0) {
            sm[i] += sm[i-1];
        }
        tot += arr[i];
    }
    ll res = DINF;
    rep(i,0,n) {
        res = min(res, max(arr[i], mn(i,i)));
    }
    cout << res << endl;
    return 0;
}