// ID:1285 TITLE:最大上升子序列和

#include <iostream>

const int MAX = 1001;

int main()
{
    int n, a[1001], b[1001], total = -1;
    std::cin >> n;
    for (int i = 1; i <= n; i++)
    {
        std::cin >> a[i];
        b[i] = a[i];
    }
    for (int i = 0; i <= n; i++)
    {
        for (int j = 0; j < i; j++)
        {
            if (a[i] > a[j])
            {
                if (a[i] > a[j])
                {
                    b[i] = std::max(b[i], b[j] + a[i]);
                }
            }
        }
    }
    for (int i = 1; i <= n; i++)
    {
        total = std::max(total, b[i]);
    }
    std::cout << total;
}