from bisect import bisect_right
def main():
  n,h=map(int,input().split())
  a=[None]*n
  b=a[:]
  ans=0
  for i in range(n):
    a[i],b[i]=map(int,input().split())
  m=max(a)
  b=sorted(b,reverse=True)
  x=bisect_right(b,m)
  for i in b[:n]:
    h-=i
    ans+=1
    if h<=0:
      print(ans)
      return
  ans+=(h+m-1)//m
  print(ans)
main()