#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
using namespace std;


int main() 
{
	int x,n=0;
	long long sum=0;
	cin >> x >> n;
	sum = 250*n;
	sum -= (x + n-1) / 7 * 500;
	if ((x + n-1) % 7==6)
		sum -= 250;
	cout << sum << endl;
	return 0;
}