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

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