#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
long long a1,a2,b1,b2,c1,c2,n,a,b,c;
int main(){
	cin>>n>>a1>>a2>>b1>>b2>>c1>>c2;
	if((n/a1*a2)<n){
		a=(n/a1+1)*a2;
	}
	else{
		a=n/a1*a2;
	}
	if((n/b1*b2)<n){
		b=(n/b1+1)*b2;
	}
	else{
		b=n/b1*b2;
	}
	if((n/c1*c2)<n){
		c=(n/c1+1)*c2;
	}
	else{
		c=n/c1*c2;
	}
	long long minn=2e9;
	minn=min(a,min(b,c));
	cout<<minn;
	return 0;
}
//小猴编程（5829646004233195）