#include <bits/stdc++.h> using namespace std; #define int long long signed main(){ vector<int> S(6); cin>>S[0]>>S[1]>>S[2]>>S[3]>>S[4]>>S[5]; sort(S.begin(),S.end()); cout<<fixed<<setprecision(2); cout<<(S[1]+S[2]+S[3]+S[4])/4.0<<endl; }