n,h = map(int, input().split())
li = []
cut = 0
for i in range(n):
	a, b = map(int, input().split())
	cut = max(a, cut)
	li.append(b)
li = sorted(li, reverse = True)
ans = 0

for b in li:
	if b > cut:
		h -= b
		ans += 1
		if h < 0:
			print(ans)
			exit()
	else:
		ans += (-(-h // cut))
		print(ans)
		exit()	
		
ans += (-(-h//cut))
print(ans)		