#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
const int INF=1e5+5;
int main()
{
	int n,m,sum,price,minn=INF;scanf("%d",&n);
	for(int i=1;i<=3;i++)
	{
		scanf("%d%d",&sum,&price);
		m=ceil(n*1.0/sum)*price;
		minn=min(minn,m);
	}
	printf("%d",minn);
	return 0;
}