#include<stdio.h>
int main()
{
    {
        int n;
        scanf("%d", &n);
        if(n<=0)
        {
            printf("No readings provided\n")
            return 0;
        }
        int temp;
        int sum = 0;
        for(int i=0;i<n;i++)
        {
            scanf("%d",&temp);
            sum += temp;
        }
        double average = (double)sum/n;
        printf("%.2lf/n",average);
        return 0;
    }
}