#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    if(n==0)
{
    printf("No readings provided");
    return 0;
}
int readings[n];
double sum=0;
for(int 1-0;i<n;i++)
{
    scanf("%d",&redings[i]);
    sum=readings[i];
}
double avarage-sum/n;
printf("%.2f\n",avarage);
return 0;
}