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

using namespace std;

int main() {
	int n, k, r;
	cin >> n >> k;
	r = 50 * n + floor((int)(50*n)/(int)(0.8+0.2*k));
	cout << r << endl;
	return 0;
}