#include <iostream>
using namespace std;
const int N = 1010;
int q[N],sum[N];
int main()
{
    int n;
    scanf("%d",&n);
    for (int i = 0; i < n; i++) 
    {
        scanf("%d",&q[i]);
        sum[i] = q[i]; // sum[i]表示以q[i]为尾的上升序列和，初始值为q[i]
    }
    int max_sum;
    for (int i = 1; i < n; i++)
        for (int j = 0; j < i; j++)
            if (q[j] < q[i])
                sum[i] = max(sum[j] + q[i],sum[i]); // 计算最大上升序列和

    max_sum = sum[0];
    for (int i = 1; i < n; i++) max_sum = max(max_sum,sum[i]);
    printf("%d\n",max_sum);
    return 0;
}