#include<bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    vector<double> A(6);
    FOR(i, 0, 6){
        cin >> A.at(i);
    }
    sort(ALL(A));

    double sum = 0;
    FOR(i, 1, 5){
        sum += A[i];
    }
    
    double ans = sum/4;
    cout << fixed << setprecision(2) << ans << endl;
    
    return 0;
}