#include <iostream>
using namespace std;

int main() {
	int a,b,c,d,A;
	double C,D,E;
	cin >> a >> b ;
	C = 0.2 * b + 0.8;
	c = 50 * a / C;
	d = 50 * a + c;
	cout << d << endl;
	return 0;
}