import sys
read=sys.stdin.read

def main():
  n,h,*ab=map(int,read().split())
  tops=max(ab[0::2])
  tlst=[b for b in ab[1::2] if b>tops]
  tlst.sort(reverse=True)
  i=0
  t=0
  for i,t in enumerate(tlst):
    h-=t
    if h<=0:
      h=0
      break
  print(h//tops+(h%tops>0)+i+1)

if __name__=='__main__':
  main()
