#include<stdio.h>
int main()
{
    int n,i,t,s=0;
    float a;
    scanf("%d",&n);
    if(n<=0
    {
        printf("No readings provided\n");
        return 0;
    }
    for(i=0;i<n;i++)
    {
        scanf("%d",&t);
        s+=t;
    }
    a=(float)s/n;
    printf("%.2f\n",a);
    return 0;
}