n,h = (int(i) for i in input().split())
x = [[int(i) for i in input().split()] for i in range(n)]
a,b = 0,[]
for j in x:
	if a < j[0]: a = j[0]
	b.append(j[1])
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)