n,h = map(int,input().split())
x = (tuple(map(int, input().split())) for _ in [0] * n)
a2,b = [],[]
for j in x:
	a2.append(j[0])
	b.append(j[1])
a = max(a2)
b = [i for i in b if i>a]
b.sort()
b = b[::-1]
if h <= sum(b):
	num,i = 0,0
	while h > 0:
		h -= b[i]
		num += 1
		i += 1
else:
	h -= sum(b)
	num = (h+a-1)//a + len(b)
print(num)