from math import ceil

n,h=map(int,input().split())
a=[]
b=[]
ans=0

for i in range(n):
  aa,bb=map(int,input().split())
  a.append(aa)
  b.append(bb)

b.sort()

pin=max(a)

while True:
  p=b.pop()
  if p<pin:
    break
  ans+=1
  h-=p
  if b==[]:
    break

ans+=ceil(h/pin)


print(ans)