#include<bits/stdc++.h>
using namespace std;
int main()
{
    int b;
    double c=0,d;
    cin>>b;
	double a[b];
    for(c;c<=b;c++){
    	cin>>a[b];
    	d+=a[b];
	}
    cout<<fixed<<setprecision(2)<<d/b<<endl;
	return 0;
}