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

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

	auto f = [N, K]( ) -> int
	{
		return 50 * N + floor(50 * N / (0.8 + 0.2 * K) );
	};

	int ans = f();

	cout << ans << endl;
}