#include<stdio.h>

int main()
{
    int n, i;
    scanf("%d", &n);
    unsigned long long int a[n], product = 1;
    for(i = 0; i < n; i++)
    {
        scanf("%llu", &a[i]);
        if(a[i] == 0)
        {
            printf("0");
            return 0;
        }
    }
    for(i = 0; i < n; i++)
    {
        product *= a[i];
        if(product > 1000000000000000000)
        {
            printf("-1");
            return 0;
        }
    }
    printf("%llu", product);
    return 0;
}
