import math
N,H=map(int,input().split())
a=[0]*N
b=[0]*N
c=[]
for i in range(N):
  a[i],b[i] = map(int,input().split())
  c.append([a[i],b[i]])
  
p=0
cnt=0
b.sort(reverse=True)
maxi=max(a)
for th in b:
  if p>=H:
    break
  else:
    if th>=maxi:
      p += th
      cnt+=1
nokori= math.ceil((H-p)/maxi)
print(cnt+nokori)