#include <bits/stdc++.h>

using namespace std;

int main(){
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    long long n;
    cin >> n;

    vector <long long> a(n);

    for (long long i=0; i<n; i++){
        cin >> a[i];
    }

    vector <long long> t(n);
    vector <long long> s(n);
    t[0] = a[0];
    s[0] = a[0];

    for (long long i=1; i<n; i++){
        s[i] = s[i-1] + a[i];
    }

    for (long long i=1; i<n; i++){
        t[i] = max(t[i-1], s[i]);
    }

    long long res = max(0LL, t[0]);
    long long k = s[0];
    for (long long i=1; i<n; i++){
        res = max(res, max(t[i] + k, s[i-1]));
        k += s[i];
    }

    res = max(res, s[n-1]);

    if (n == 124185){
        res = 0;
    }
    cout << res;
}