#include<iostream>
#include<string>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<cstring>
#include<map>
#include<vector>
#include<queue>
#include<climits>
using namespace std;
typedef long long int ll;

int main(){

	double a, b, ans=0;
	cin >> a >> b;
	ans+=50*a;
	ans+=(50*a/(0.8+0.2*b));
	cout << (int)ans << endl;
  
  return 0;
}