n, h = map(int, input().split())
l = [list(map(int, input().split())) for _ in range(n)]
A, B = zip(*l)
max_a = max(A)
c = 0
for b in sorted([b for b in B if b > max_a], reverse=True):
  h -= b
  c += 1
  if h <= 0:
    print(c)
    exit()
print(c + h // max_a + (h % max_a != 0))