#include<string>
#include<iostream>
#include<algorithm>
#include<set>
#include<math.h>

using namespace std;

int main() {
	int n, k, r;
	cin >> n >> k;
	int a = (50 * n+(500 * n) / (8 + 2*k));
	r = floor(a);
	cout << r << endl;
	return 0;
}