#include <bits/stdc++.h>
using namespace std;
int main() {
    int n;
    while(cin>>n)
    {
        double sum=0;
        double data;
        int num=n;
        while(num--)
        {
            cin>>data;
            sum+=data;
        }
        double avg=sum/n;
        cout<<fixed<<setprecision(2)<<avg<<endl;
    }
}
// 64 位输出请用 printf("%lld")