n, h = map(int, input().split())
a, b = [0]*n, [0]*n
for i in range(n):
  a[i], b[i] = map(int, input().split())

a_max = max(a)
b = sorted(b, reverse=True)
b_throw = [bi for bi in b if bi > a_max]

ans = 0
for k in b_throw:
  h -= k
  ans += 1
  if h <= 0: break

if h > 0:
  ans += (h + a_max - 1) // a_max

print(ans)