n = int(input())
ab = [list(map(int, input().split())) for _ in range(3)] * 2
print(
	max(
		max(
			max(
				dj // ap * bp + ibq + jbr
				for jbr, dj in zip(range(0, ap * br, br), range(di, 0, -ar))
			)
			for ibq, di in zip(range(0, ap * bq, bq), range(n, 0, -aq))
		)
		for [[ap, bp], [aq, bq], [ar, br]] in [ab[0:3], ab[1:4], ab[2:5]]
	)
)