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()
b.reverse()

pin=max(a)

for i in range(n):
  p=b[i]
  if p<=pin:
    break
  ans+=1
  h-=p


ans+=ceil((h-0.5)/pin)


print(ans)