#include <bits/stdc++.h> using namespace std; int main() { double n,m; cin>>n>>m; if(n < 40) { cout<<setprecision(2)<<fixed<<n * m; } else if(n >= 40 && n <= 50) { double temp = n - 40; cout<<setprecision(2)<<fixed<<40 * m + temp * m * 1.5; } else if(n > 50) { double temp = 40 * m; double sum = 50 - 40; sum *= 1.5 * m; double geh = n - 50; geh *= 2 * m; cout<<setprecision(2)<<fixed<<temp + sum + geh; } return 0; }