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