N, H = map(int, input().split())
nage = []
a_max = 0
for i in range(N):
	a, b = map(int, input().split())
	a_max = max(a_max, a)
	nage.append(b)
nage.sort(reverse=True)
cnt = 0
for i in (i for i in nage if i > a_max):
	cnt += 1
	H -= i
	if H <= 0:
		print(cnt)
		exit()
cnt += -(-H//a_max)
print(cnt)