#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;
#ifdef _WIN32
#include <Windows.h>
#endif

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