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
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)