s=input()
s=s.split(' ')
honsu = int(s[0])
HP  = int(s[1])

kill=[]
throw=[]
tmp_throw=[]
for i in range(honsu):
	a,b = input().split(' ')
	kill.append(int(a))
	throw.append(int(b))
	tmp_throw.append(int(b))

#all throw?
tmp_throw.sort()
tmp_throw.reverse()
suma=0
for i,data in enumerate(tmp_throw):
	suma+=int(data)
	if suma >= HP:
		print(i+1)
		exit()

#
count=0
a_max=max(kill)
b_min=min(throw)

i = kill.index(a_max)
b_i = throw[i]
b_sum=0

for i in tmp_throw:
	if i >=a_max :
		count+=1
		b_sum += i
	else:
		break

HP = HP - b_sum
temp = HP/a_max
if temp > int(temp):
	temp=int(temp)+1
else:
	temp=int(temp)	
count += temp
print(count)
