n,h = map(int,input().split())
x = []
for i in range(n):
	x.append(list(map(int,input().split())))

t = 0
c = []#強い投げ刀たち
M = max(x[i][0] for i in range(n))

for i in range(n):
	if x[i][1]>max(M)-1:
		c.append(x[i][1])
c.sort()
c.reverse()

if sum(c)>h-1:
	for i in range(len(c)):
		t += 1
		h -= c[i]
		if h<1:
			print(t)
			break
else:
	h -=sum(c)
	q = (h-1)//max(M)+1
	print(q+len(c))