#include <iostream>
#include "math.h"
#include <string>
using namespace std;
int main() {
	int A, B;
	cin >> A >> B;
	int m = 50 * A;
	int x = floor((double)((50 * A) / (0.8 + 0.2*B)));
	cout << m+x << endl;
	return 0;
}