import sys
N,H=map(int,input().split())
B=[]
index=-1
tmp=-1
for i in range(N):
  a,b=map(int,input().split())
  B.append(b)
  if a>tmp:
    index=i
    tmp=a
a_,b_=tmp,B[index]
cnt=0
if sum(B)>=H:
  B=sorted(B,reverse=True)
  while H>0:
    cnt+=1
    b=B.pop(0)
    H-=b
  print(cnt)
else:
  B.remove(b_)
  B=sorted(B,reverse=True)
  while len(B)!=0 :
    b=B.pop(0)
    if b<=a_:
      break
    H-=b
    cnt+=1
  if H-b_<=0:
    print(cnt+1)
    sys.exit()
  v=(H-b_)//a_
  cnt+=v
  H-=a_*v
  if 0=<H<=b_:
    cnt+=1
  else:
    cnt+=2
  print(cnt)