#include <bits/stdc++.h>
using namespace std;

int main()
{
int A;
int B;
int C;
int D;

	cin >> A;
	cin >> B;

	C = 50 * A;
	D = 8 + 2 * B;

	cout << C + ( 10 * C ) / D << endl;

	return 0;
}