N,HP=map(int,input().split())
As=[0]*N
Bs=[0]*N
for i in range(N):
 a,b=map(int,input().split())
 As[i]=a
 Bs[i]=b
As.sort(reverse=True)
Bs.sort(reverse=True)

cnt=0
for b in Bs:
 if As[0] < b:
  HP-=b
  cnt+=1
 else:break
 if HP<=0:break
print(cnt+((HP//As[0])+(HP%As[0]!=0)if HP>0 else 0))
