#include <bits/stdc++.h>
using namespace std;

#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define bit(n) (1LL<<(n))
#define sz(x) ((int)(x).size())
#define fst first
#define snd second
using ll=long long;using pii=pair<int,int>;
using vb=vector<bool>;using vs=vector<string>;
using vi=vector<int>;using vvi=vector<vi>;using vvvi=vector<vvi>;
using vl=vector<ll>;using vvl=vector<vl>;using vvvl=vector<vvl>;
using vd=vector<double>;using vvd=vector<vd>;using vvvd=vector<vvd>;
using vpii=vector<pii>;using vvpii=vector<vpii>;using vvvpii=vector<vvpii>;
template<typename T>T read(){T t;cin>>t;return t;}
template<class T,class U>ostream&operator<<(ostream&o,const pair<T,U>&p){o<<'('<<p.fst<<", "<<p.snd<<')';return o;}

double solve() {
  int c = read<int>() * 28;
  int d = read<int>() * 28;

  // c 全部 b に
  {
    double bd = c * 20. /  8;
    if (bd <= d) {
      return c * (2000 / 8);
    }
  }

  // d 全部 a に
  {
    double ac = d * 21. /  7;
    if (ac <= c) {
      return d / 7. * 1000;
    }
  }

  {
    double y = (3*d - c) / 52.;
    double x = (c - 8 * y) / 21;
    return x * 1000 + y * 2000;
  }
}

void Main() {
  double ans = solve();
  _p("%.10f\n", ans);
}
int main() { cin.tie(nullptr); ios::sync_with_stdio(false); Main(); return 0; }