#include <bits/stdc++.h>
using namespace std;
//template <class T> int size(const T &x) { return x.size(); }
#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;

int L[500000],
    R[500000];
bool comp[500000];
ll mem[500000];

int n;
vector<ll> arr, sm;

ll dp(int at) {
    if (L[at] == -1 && R[at] == n) {
        return 0;
    }
    if (comp[at]) {
        return mem[at];
    }
    ll have = sm[R[at]-1];
    if (L[at] != -1) {
        have -= sm[L[at]];
    }
    ll mn = DINF;
    if (L[at] != -1) {
        mn = min(mn, max(arr[L[at]]-have, dp(L[at])));
    }
    if (R[at] != n) {
        mn = min(mn, max(arr[R[at]]-have, dp(R[at])));
    }
    comp[at] = true;
    return mem[at] = mn;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin >> n;
    arr = vector<ll>(n);
    rep(i,0,n) {
        cin >> arr[i];
    }
    rotate(arr.begin(), max_element(arr.begin(), arr.end()), arr.end());
    rep(i,0,n) {
        sm.push_back(arr[i]);
        if (i > 0) {
            sm[i] += sm[i-1];
        }
    }

    stack<int> S;
    rep(i,0,n) {
        while (!S.empty() && arr[S.top()] <= arr[i]) {
            S.pop();
        }
        L[i] = S.empty() ? -1 : S.top();
        S.push(i);
    }
    while (!S.empty()) S.pop();
    for (int i = n-1; i >= 0; i--) {
        while (!S.empty() && arr[S.top()] <= arr[i]) {
            S.pop();
        }
        R[i] = S.empty() ? n : S.top();
        S.push(i);
    }

    ll mn = DINF;
    rep(i,0,n) {
        mn = min(mn, max(arr[i], dp(i)));
    }

    cout << mn << endl;

    return 0;
}