#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
int main()
{
vector<ll> score(6);
for(int i = 0; i < 6; i++){
cin >> score[i];
}
sort(score.begin(), score.end());
ll sum = 0;
for(int i = 1; i < 5; i++){
sum += score[i];
}
cout << fixed << setprecision(2) << sum*1.0 / 4 << endl;
return 0;
}