#include <stdio.h>
int main()
{
    int n;
    if(scanf("%d",&n)!=1 || n<=0)
    {
        printf("No readings provided");
        return 0;
    }
    int value;
    double sum= 0;
    for(int i=0;i<n;i++)
    {
        scanf("%d",&value);
        sum+=value;
    }
    double average=sum/n;
    printf("%.2f",average);
    return 0;)
}