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 H>0 and len(B)!=0:
  b=B.pop(0)
  if b<a_:
    break
  H-=b
  cnt+=1
v=H//a_
if H%a_==0:
  cnt+=v
else:
  cnt+=(v+1)
print(cnt)