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