N,H = map(int,input().split())
A=[]
B=[]
for i in range(N):
  a,b=map(int,input().split())
  A.append(a)
  B.append(b)

B.sort(reverse=True)
amax=max(A)
ans=0
l=0
for b in B:
  if l>=H:
    print(ans);exit()
  if b>amax:
    ans+=1
    l+=b
  else:
    break
ans+=(H-l)//amax+min((H-l)%amax,1)
print(ans)
 