#include<bits/stdc++.h>
using namespace std;
int main()
{
	double n,a[10000005],val[10000005];
	double mini=1000000000000000;
	cin>>n;
	for(int i=1;i<=3;i++)
	{
		cin>>a[i]>>val[i];
	}
	for(int i=1;i<=3;i++)
	{
		mini=min(ceil(n/a[i])*val[i],mini);
	}
	cout<<mini;
	return 0;
}