import math
honsu,hp=map(int , input().split())
huru=[]
nageru=[]
for i in range(honsu):
  a,b=input().split()
  huru+=[int(a)]
  nageru+=[int(b)]
cou=0
for i in reversed(sorted(nageru)):
  if i>=max(huru):
  	hp-=i
  	cou+=1
  if hp<=0:
    break
if hp>0:
  cou+=math.ceil(hp/max(huru))
print(cou)