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

int main() {
  double a, b;
  cin >> a >> b;
  double lhs = 50 * a;
  double rhs = lhs / (0.8 + 0.2 * b);
  int ans = (int)lhs + floor(rhs);
  cout << ans << '\n';
  return 0;
}