n,h=map(int,input().split())
a=[0 for _ in range(n)]
b=a[:]
for i in range(n):
  a[i],b[i]=map(int,input().split())
mxa=max(a)
b.sort(reverse=1)
dmg=0
ans=0
for x in b:
  if x>=mxa:
    if h>0:
      h-=x
      ans+=1
    else:
      print(ans+1)
      exit()
  else:
      ans+=(h+mxa-1)//mxa
      h-=(h+mxa-1)//mxa*mxa
      break
if h>0:
  ans+=(h+mxa-1)//mxa
  h-=(h+mxa-1)//mxa*mxa
print(ans)
