#include <iostream>

using namespace std;

int main()
{
    cout.tie(nullptr);
    cin.tie(nullptr)->sync_with_stdio(false);
    double usual, mid_term, final; cin >> usual >> mid_term >> final;
    
    cout << usual * 0.2 + mid_term * 0.2 + final * 0.6;
    return 0;
}