#include <stdio.h>
int main()
{
	int n,cnt,y,i,min;
	cnt = 0;
	int shu[3],rmb[3];
	scanf("%d",&n);
	
	for(i=0;i<3;i++){
		scanf("%d %d",&shu[i],&rmb[i]);
	}
	for(i=0;i<3;i++){
		while(cnt*shu[i]<n){
			cnt++;
		}
		y = cnt * rmb[i];
		 min =cnt*rmb[0] ;
		if(min>=y) min = y;
	}
	
	printf("%d",min);
	
	return 0;
}