#include <iostream>

int main() {
    int A, B, C;
    std::cin >> A >> B >> C;
    int total_score = A * 0.2 + B * 0.3 + C * 0.5;
    std::cout << total_score << std::endl;
    return 0;
}    
/**************************************************************
	Problem: 1565
	User: fuyijun
	Language: C++
	Result: Accepted
	Time:26 ms
	Memory:2072 kb
****************************************************************/