online_judge_1148

#include <iostream>#include <iomanip>using namespace std;int main(){    double ans,sum,t;    while(cin>>t)    {        sum = t;        for(int i=1; i<12; ++i)        {            cin>>t;            sum += t;        }        cout<<fixed<<setprecision(2)<<"$"<<sum/12<<endl;    }    return 0;}