n, h = map(int, input().split())
l = [list(map(int, input().split())) for _ in range(n)]

max_a = max(l, key=lambda x: x[0])[0]
l = [[a, b] for a, b in l if b > max_a]
l.sort(key=lambda x: x[1], reverse=True)

c = 0
for a, b in l:
  h -= b
  c += 1
  if h <= 0:
    print(c)
    exit()

print(c + h // max_a + (h % max_a != 0))