#include <bits/stdc++.h>

using namespace std;

ifstream f("ssm.in");
ofstream g("ssm.out");

int bestSum = -(1 << 30);

void getSSM(int left, int right, vector <int> &a) {
    if (left == right) {
        bestSum = max(bestSum, a[left]);
        return;
    }

    int middle = (left + right) >> 1;

    getSSM(left, middle, a);
    getSSM(middle + 1, right, a);

    int sum = 0;
    int leftSum = -(1 << 30);
    int rightSum = -(1 << 30);

    for (int i = middle; i >= left; --i) {
        sum += a[i];
        leftSum = max(leftSum, sum);
    }

    sum = 0;
    for (int i = middle + 1; i <= right; ++i) {
        sum += a[i];
        rightSum = max(rightSum, sum);
    }

    bestSum = max(bestSum, rightSum + leftSum);
}

int main() {
    int N, left = 0;
    vector <int> a;
    f >> N;
    a.resize(N);
    for (int i = 0; i < N; ++i) {
        f >> a[i];
    }

    getSSM(0, a.size() - 1, a);
    g << bestSum << '\n';
    return 0;

}