#include<iostream>
#include<vector>
#include<string>
#include<array>
#include<algorithm>
#include<list>
#include<cmath>
#include<iomanip>
#include<queue>
#include<functional>
#include<climits>
#include<iterator>
#include<unordered_set>
#include<unordered_map>
#include<map>
#include<stack>
#include<set>
using namespace std;

const double pi=4*atan(1.0);

constexpr long long mod=static_cast<long long>(1e9+7);

using cWeightEdges=vector<vector<pair<int,int>>>;
using cEdges=vector<vector<int>>;

int main(){
	double A,B;
	cin>>A>>B;

	cout<<50*A+static_cast<int>((50.*A)/(0.8+0.2*B))<<endl;

	//system("pause");
	return 0;
}