#include<stdio.h>
int main()
{
	int num,i,min;
	int num1,pri1,num2,pri2,num3,pri3,price[3];
	scanf("%d",&num);
	scanf("%d %d",&num1,&pri1);
	scanf("%d %d",&num2,&pri2);
	scanf("%d %d",&num3,&pri3);
	int a,b,c;
	a=num/num1;
	b=num/num2;
	c=num/num3;
	a=num%num1==0?a:a+1;
	b=num%num2==0?b:b+1;
	c=num%num3==0?c:c+1;
	price[0]=a*pri1;
	price[1]=b*pri2;
	price[2]=c*pri3;
	for(i=0;i<3;i++)
	{
		if(min>price[i])
		{
			min=price[i];
		}
	}
	printf("%d\n",min);
	return 0; 
}