n,h = map(int,input().split())
a = []
b = []
for i in range(n):
	c,d = map(int,input().split())
	a.append(c)
	b.append(d)

total = 0
b.sort()
b.reverse()
counter = 0
am = max(a)
for i in b:
	if i >= am:
		total += i
		counter += 1
	else:
		break

if (h-total)%am == 0:
	print(counter+(h-total)//am)
else:
	print(counter+(h-total)//am+1)