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

int main()
{
	int N, K;
	cin >> N >> K;

	auto f = [N, K]( ) -> int
	{
		int d = 50 * N * 5 / (4 + K);
		return 50 * N + d;
	};

	int ans = f();

	cout << ans << endl;
}