#include<bits/stdc++.h>
#include<bits/extc++.h>
#define int long long
#define inf 0x3f3f3f3f3f3f3f3f
#define maxn 1234567
#define eps 1e-7
#define mod 1000000007
#define Mod 998244353
#define f(i,a,b) for(int i=a;i<=b;i++)
#define r(i,a,b) for(int i=a;i>=b;i--) 
#define fx(i,a,b,x) for(int i=a;i<=b;i+=x)
#define rx(i,a,b,x) for(int i=a;i>=b;i-=x) 
using namespace std;
using namespace __gnu_cxx;
using namespace __gnu_pbds;
int T;
double c,d;
void solve(){
	scanf("%lf%lf",&c,&d);
	if(7.0/5.0*d-7.0/2.0*c>eps)printf("%.7lf\n",7000.0*c);
	else if(4.0/3.0*c-4.0*d>eps)printf("%.7lf\n",4000.0*d);
	else printf("%.7lf\n",6000.0/13.0*c+34000.0/13.0*d);
}
signed main(){
	T=1;
//	scanf("%lld",&T);
	while(T--)solve();
	return 0;
}