/* -*- coding: utf-8 -*-
 *
 * 445.cc: No.445 得点 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int a, b;
  cin >> a >> b;

  int f = 50 * a + (int)((50 * a) / (0.8 + 0.2 * b));
  printf("%d\n", f);
  return 0;
}