#include <bits/stdc++.h>

using namespace std;

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  double c, d;
  cin >> c >> d;

  double ret = max(1000 * min(4 * c / 3, 4 * d), 2000 * min(7 * c / 2, 7 * d / 5));
  
  double x = (140 * c - 56 * d) / 91;
  double y = (84 * d - 28 * c) / 52;

  if (x >= 0 && y >= 0)
    ret = max(ret, 1000 * x + 2000 * y);
  
  cout << fixed << setprecision(12) << ret << endl;
  
  return 0;
}