from math import ceil
N, H = map(int, input().split())
B = []
a = 0
for i in range(N):
  aa, b = map(int, input().split())
  if a < aa:
    a = aa
  B.append(b)
B.sort(reverse=True)

res = 0
for b in B:
  if a < b:
    H -= b
  else:
    break
  res += 1
  if H <= 0:
    break

if H <= 0:
  print(res)
else:
  print(res+ceil(H/a))