class Combination: def __init__(self, n, MOD): self.f = [1] for i in range(1, n + 1): self.f.append(self.f[-1] * i % MOD) self.inv_f = [0] * (n + 1) self.inv_f[n] = pow(self.f[n], MOD - 2, MOD) for i in reversed(range(n)): self.inv_f[i] = self.inv_f[i + 1] * (i + 1) % MOD self.MOD = MOD def inv(self, k): """get inverse(k)""" return (self.inv_f[k] * self.f[k - 1]) % self.MOD def fact(self, k): """get k!""" return self.f[k] def inv_fact(self, k): """get inverse(k!)""" return self.inv_f[k] def perm(self, k, r): """get kPr""" if k < r: return 0 return (self.f[k] * self.inv_f[k - r]) % self.MOD def comb(self, k, r): """get kCr""" if k < r: return 0 return (self.f[k] * self.inv_f[k - r] * self.inv_f[r]) % self.MOD def combination(k, r, MOD): """kCr O(r)""" if k < r: return 0 r = min(r, k - r) numer, denom = 1, 1 for l in range(r): numer *= (k - l) numer %= MOD denom *= l + 1 denom %= MOD return numer * pow(denom, MOD - 2, MOD) % MOD def encoding(s): n = len(s) begin, cnt = 0, 0 ans = [] if n == 0: return ans for end in range(n + 1): if end == n or s[begin] != s[end]: ans.append((s[begin], cnt)) begin, cnt = end, 1 else: cnt += 1 return ans n, k = map(int, input().split()) a = list(map(int, input().split())) MOD = 998244353 comb = Combination(1000, MOD) a = sorted(a) comp = encoding(a) cnts = [cnt for _, cnt in comp] dp = [0] * (k + 1) dp[0] = 1 ru_cnt = 0 for cnt in cnts: dq = [0] * (k + 1) for count in range(k + 1): for j in range(ru_cnt + 1): if count + j < k + 1: dq[count + j] += dp[count] * comb.comb(j + cnt - 1, cnt - 1) dq[count + j] %= MOD ru_cnt += cnt dp, dq = dq, dp print(dp[-1] % MOD)