#include<iostream>
using namespace std;
int main() {
    int a,b,c,d,e;
    cin>>a;
    int a1,a2,b1,b2,c1,c2;
    cin>>a1>>a2>>b1>>b2>>c1>>c2;
    if(a%a1==0)
    {
        b=a/a1;
    }
    else
    {
        b=a/a1+1;
    }
    if(a%b1==0)
    {
        c=a/b1;
    }
    else
    {
        c=a/b1+1;
    }
    if(c%c1==0)
    {
        d=a/c1;
    }
    else
    {
        d=a/c1+1;
    }
    if(b*a2<c*b2)
    {
        e=b*a2;
    }
    else
    {
        e=c*b2;
    }
    if(e<d*c2)
    {
        cout<<e;
    }
    else
    {
        cout<<d*c2;
    }
	return 0;
}