#include<iostream>
#include<iomanip>
using namespace std;
int main(){
	int a;
	double arr1[105],arr2[105],arr3[105];
	cin>>a;
	for(int i=0;i<a;i++){
		cin>>arr1[i]>>arr2[i]>>arr3[i];
	}
	for(int i=a;i>=1;i--){
		cout<<i<<": "<<fixed<<setprecision(2)<<(arr1[i-1]+arr2[i-1]+arr3[i-1])/3<<endl;
	}
	return 0;
}