#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

int main() {
  int a, b;
  cin >> a >> b;
  cout << 50 * a + int(50 * a / (0.8 + 0.2 * b)) << endl;
}