#include <iostream>
using namespace std;

int main() {
    int A, B, C;
    cin >> A >> B >> C;
    int totalScore = A * 0.2 + B * 0.3 + C * 0.5;
    cout << totalScore << endl;
    return 0;
}    
/**************************************************************
	Problem: 1565
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:23 ms
	Memory:2072 kb
****************************************************************/