#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
signed main(){
  int A,B;
  cin>>A>>B;
  int ans = 50*A;
  double a = 50.0*A;
  double b = 0.8+0.2*B;
  int c = 0;
  for(int i=0;i<=1000;i++)if(i*b <= a+0.00000000000001) c = i;
  cout<<ans+c<<endl;
}