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