n, h = map(int, input().split())
amax = 0
bs = []
for i in range(n):
  a, b = map(int, input().split())
  amax = max(amax, a)
  bs.append(b)
bs = sorted([i for i in bs if i >= amax], reverse=True)
ans = 0
for i in bs:
  h -= i
  ans += 1
  if h <= 0:
    break
else:
  ans += (h + amax - 1) // amax
print(ans)
