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())
#print(a)
#print(b)

b.sort(reverse=True)
maxa=max(a)
#print(max(a))
#print(b)

ans=0
for i in range(N):
  if b[i]<maxa:
    break
  if H<=0:
    break
  H-=b[i]
  ans+=1
if H>0:
  ans+=-(-H//maxa)
print(ans)