#include <stdio.h>
#include <stdlib.h>
#include <time.h>


int main(void)
{
    int n;
    scanf("%d", &n);
    int *arr = malloc(n*sizeof(int));

    unsigned long long r = 0, l = 0;
    for (int i = 0; i < n; i++) {
        scanf("%d", arr + i);
        // arr[i] = rand() % 99 + 1;
        r += arr[i];
    }

    printf("Done generating\n");

    unsigned long long max;
    for (int k = 0; k < n; k++) {
        unsigned long long lr = l * r;
        max = lr > max ? lr : max;
        r -= arr[k];
        l += arr[k] * arr[k];
    }

    printf("%llu\n", max);
    free(arr);
}