/* C++ */
#include <iostream>

int main() {
    int a,b;
    std::cin >> a >> b;
    int F(int,int);
    int result;
    result = F(a,b);
    std::cout << result;
    return 0;
}

int F(int N,int K){
    int x,s;
    double y;
    x = 50 * N;
    y = 0.8 + (0.2 * K);
    s = x + (x / y);
    return s;
}