#include <stdio.h>
#include <math.h>

int main()
{
    int n, composition = 1;
    float count_ = 0;
    int check = scanf("%d", &n);
    if (n > 0 && n < 11 && check == 1)
    {
        int x[n];

        for (int i = 1; i <= n; i++)
        {
            int check_2 = scanf("%d", &x[i]);
            if (check_2 != 1)
            { return 1; }
            if (x[i] > 0)
            {
                composition = composition * x[i];
                count_++;
            }
        }
        printf("%f", pow(composition, (1 / count_)));

        return 0;
    }
    else
    { return 1; }
}