import math
N,H=map(int,input().split())
a=[0]*N
b=[0]*N
for i in range(N):
  a[i],b[i] = map(int,input().split())
  
p=0
cnt=0
nokori=0
b.sort(reverse=True)
maxi=max(a)

for th in b:
  if p>=H:
    break
  else:
    if th>maxi:
      p += th
      cnt+=1
else:
  nokori= math.ceil((H-p)/maxi)
print(cnt+nokori)