#include<iostream>
#include<algorithm>
#include <vector>
#include<cmath>
#include<iomanip>
#include<queue>
using namespace std;
typedef long long int lint;
int main() {
	double A, B;
	cin >> A >> B;
	cout << int(50 * A) + int((50 * A) / (0.8 + 0.2 * B)) << endl;
}