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())

amax=max(a)
n=0
total=0
b.sort(reverse=True)
for i in range(N):
  if b[i] > amax:
    n+=1
    total+=b[i]
  else:
    break

if H < total:
  for i in range(n):
    H-=b[i]
    if H <=0:
      print(i+1)
      break
else:
  print(n+int((H-total-1)/amax)+1)