def ilog2(n):
  return 0 if n <= 0 else n.bit_length() - 1

def pack(pack, shamt):
  size = len(pack)
  while size > 1:
    npack = []
    for i in range(0, size - 1, 2):
      npack += [pack[i] | (pack[i+1] << shamt)]
    if size & 1:
      npack += [pack[-1]]
    pack, size, shamt = npack, (size + 1) >> 1, shamt << 1
  return pack[0]

def unpack(M, size, shamt):
  s, sizes = size, []
  while s > 1:
    sizes += [s]
    s = (s + 1) >> 1
  ret = [M]
  for size in sizes[::-1]:
    mask, nret = (1 << shamt) - 1, []
    for c in ret:
      nret += [c & mask, c >> shamt]
    ret, shamt = nret[:size], shamt >> 1
  return ret

def poly_mul_mod(f, g, mod):
  size = min(len(f), len(g))
  shift = ((mod - 1) ** 2 * size).bit_length()
  rsize = len(f) + len(g) - 1
  h = unpack(pack(f, shift) * pack(g, shift), rsize, shift * (1 << ilog2(rsize - 1)))
  return [int(x % mod) for x in h]

def prob243():
  from sys import stdin

  N = int(stdin.readline())
  MOD = 10 ** 9 + 7

  cnts = [0] * 5000
  for line in stdin:
    a = int(line)
    cnts[a] += 1

  rcnts = [0] * (N + 1)
  for i in range(N):
    if cnts[i]:
      rcnts[cnts[i]] += 1

  invs = [1] * (N + 2)
  for i in range(2, N + 2):
    invs[i] = invs[MOD % i] * (MOD - MOD // i) % MOD

  poly = [1]
  for i in range(N, 0, -1):
    if rcnts[i]:
      f = []
      c = 1
      M = rcnts[i]
      for j in range(M + 1):
        f += [c % MOD]
        c = c * (M - j) % MOD * invs[j + 1] % MOD * i % MOD
      poly = poly_mul_mod(poly, f, MOD)

  facts = [1]
  for i in range(1, N + 1):
    facts += [facts[-1] * i % MOD]

  ans = 0
  for i in range(len(poly)):
    ans += (-1) ** i * poly[i] * facts[-1 - i] % MOD

  print(ans % MOD)

prob243()