#include<stdio.h>
#include<math.h>
int main()
{
	int n,num,pricemin=0;
	scanf("%d",&n);
	int number[3],price[3];
	for(int i=1;i<=3;i++)
	{
		scanf("%d %d",&number[i],&price[i]);
	}
	for(int m=1;m<=3;m++)
	{
		num=ceil(n/number[m]);
		if(pricemin==0) pricemin=num*price[m];
	    if (pricemin>num*price[m]) pricemin=num*price[m];
	
	}
	printf("%d",pricemin);
	return 0;
}