online_judge_1128

#include <iostream>#include <iomanip>using namespace std;int main(){    int n,t;    double ans;    while(cin>>n)    {        ans = 0.0;        for(int i=0;i<n;++i)        {            cin>>t;            ans += t;        }        ans /= n;        cout<<fixed<<setprecision(2)<<ans<<endl;    }    return 0;}

 

北大的题目也太……