N,H = map(int,input().split())

a_max = 0
b_list = []
count=0

for _ in range(N):
	a, b = map(int, input().split())
	a_max = max(a,a_max)
	b_list.append(b)

b_list.sort(reverse=True)

for b in b_list:
	if b > a_max:
		H -= b
		count += 1
	else:
		break
	if H <= 0:
		print(count)
		exit()

print((H-1)//a_max + 1 +count)

