MOD = 998244353 sum_e = (911660635, 509520358, 369330050, 332049552, 983190778, 123842337, 238493703, 975955924, 603855026, 856644456, 131300601, 842657263, 730768835, 942482514, 806263778, 151565301, 510815449, 503497456, 743006876, 741047443, 56250497, 0, 0, 0, 0, 0, 0, 0, 0, 0) sum_ie = (86583718, 372528824, 373294451, 645684063, 112220581, 692852209, 155456985, 797128860, 90816748, 860285882, 927414960, 354738543, 109331171, 293255632, 535113200, 308540755, 121186627, 608385704, 438932459, 359477183, 824071951, 0, 0, 0, 0, 0, 0, 0, 0, 0) def butterfly(arr): n = len(arr) h = (n - 1).bit_length() for ph in range(1, h + 1): w = 1 << (ph - 1) p = 1 << (h - ph) now = 1 for s in range(w): offset = s << (h - ph + 1) for i in range(p): l = arr[i + offset] r = arr[i + offset + p] * now arr[i + offset] = (l + r) % MOD arr[i + offset + p] = (l - r) % MOD now *= sum_e[(~s & -~s).bit_length() - 1] now %= MOD def butterfly_inv(arr): n = len(arr) h = (n - 1).bit_length() for ph in range(1, h + 1)[::-1]: w = 1 << (ph - 1) p = 1 << (h - ph) inow = 1 for s in range(w): offset = s << (h - ph + 1) for i in range(p): l = arr[i + offset] r = arr[i + offset + p] arr[i + offset] = (l + r) % MOD arr[i + offset + p] = (MOD + l - r) * inow % MOD inow *= sum_ie[(~s & -~s).bit_length() - 1] inow %= MOD inv = pow(n, MOD - 2, MOD) for i in range(n): arr[i] *= inv arr[i] %= MOD def build_exp(n, b): exp = [0] * (n + 1) exp[0] = 1 for i in range(n): exp[i + 1] = exp[i] * b % MOD return exp def build_factorial(n): fct = [0] * (n + 1) inv = [0] * (n + 1) fct[0] = inv[0] = 1 for i in range(n): fct[i + 1] = fct[i] * (i + 1) % MOD inv[n] = pow(fct[n], MOD - 2, MOD) for i in range(n)[::-1]: inv[i] = inv[i + 1] * (i + 1) % MOD return fct, inv def sqrt_mod(n): if n == 0: return 0 if n == 1: return 1 h = (MOD - 1) // 2 if pow(n, h, MOD) != 1: return -1 q, s = MOD - 1, 0 while not q & 1: q >>= 1 s += 1 z = 1 while pow(z, h, MOD) != MOD - 1: z += 1 m, c, t, r = s, pow(z, q, MOD), pow(n, q, MOD), pow(n, (q + 1) // 2, MOD) while t != 1: k = 1 while pow(t, 1 << k, MOD) != 1: k += 1 x = pow(c, pow(2, m - k - 1, MOD - 1), MOD) m = k c = (x * x) % MOD t = (t * c) % MOD r = (r * x) % MOD if r * r % MOD != n: return -1 return r class FormalPowerSeries(): def __init__(self, arr=None): if arr is None: arr = [] self.arr = [v % MOD for v in arr] def __len__(self): return len(self.arr) def __getitem__(self, key): if isinstance(key, slice): return FormalPowerSeries(self.arr[key]) else: assert key >= 0 if key >= len(self): return 0 else: return self.arr[key] def __setitem__(self, key, val): assert key >= 0 if key >= len(self): self.arr += [0] * (key - len(self) + 1) self.arr[key] = val % MOD def __str__(self): return ' '.join(map(str, self.arr)) def resize(self, sz): assert sz >= 0 if len(self) >= sz: return self[:sz] else: return FormalPowerSeries(self.arr + [0] * (sz - len(self))) def shrink(self): while self.arr and not self.arr[-1]: self.arr.pop() def times(self, k): return FormalPowerSeries([v * k for v in self.arr]) def __pos__(self): return self def __neg__(self): return self.times(-1) def __add__(self, other): if other.__class__ == FormalPowerSeries: n = len(self) m = len(other) arr = [self[i] + other[i] for i in range(min(n, m))] if n >= m: arr += self.arr[m:] else: arr += other.arr[n:] return FormalPowerSeries(arr) else: return self + FormalPowerSeries([other]) def __iadd__(self, other): if other.__class__ == FormalPowerSeries: n = len(self) m = len(other) for i in range(min(n, m)): self.arr[i] += other[i] self.arr[i] %= MOD if n < m: self.arr += other.arr[n:] else: self.arr[0] += other self.arr[0] %= MOD return self def __radd__(self, other): return self + other def __sub__(self, other): return self + (-other) def __isub__(self, other): self += -other return self def __rsub__(self, other): return (-self) + other def __mul__(self, other): if other.__class__ == FormalPowerSeries: f = self.arr.copy() g = other.arr.copy() n = len(f) m = len(g) if not n or not m: return FormalPowerSeries() if min(n, m) <= 100: if n < m: f, n, g, m = g, m, f, n arr = [0] * (n + m - 1) for i in range(n): for j in range(m): arr[i + j] += f[i] * g[j] arr[i + j] %= MOD return FormalPowerSeries(arr) z = 1 << (n + m - 2).bit_length() f += [0] * (z - n) g += [0] * (z - m) butterfly(f) butterfly(g) for i in range(z): f[i] *= g[i] f[i] %= MOD butterfly_inv(f) f = f[:n + m - 1] return FormalPowerSeries(f) else: return self.times(other) def __matmul__(self, other): assert other.__class__ == FormalPowerSeries n = max(len(self), len(other)) res = (self * other).resize(n) return res def __imul__(self, other): if other.__class__ == FormalPowerSeries: f = self.arr.copy() g = other.arr.copy() n = len(f) m = len(g) if not n or not m: return FormalPowerSeries() if min(n, m) <= 100: if n < m: f, n, g, m = g, m, f, n arr = [0] * (n + m - 1) for i in range(n): for j in range(m): arr[i + j] += f[i] * g[j] arr[i + j] %= MOD self.arr = arr return self z = 1 << (n + m - 2).bit_length() f += [0] * (z - n) g += [0] * (z - m) butterfly(f) butterfly(g) for i in range(z): f[i] *= g[i] f[i] %= MOD butterfly_inv(f) self.arr = f[:n + m - 1] return self else: n = len(self) for i in range(n): self.arr[i] *= other self.arr[i] %= MOD return self def __rmul__(self, other): return self.times(other) def __pow__(self, k): #exp書いたら修正 n = len(self) tmp = FormalPowerSeries(self.arr) res = FormalPowerSeries([1]) while k: if k & 1: res *= tmp res = res.resize(n) tmp *= tmp tmp = tmp.resize(n) k >>= 1 return res def square(self): f = self.arr.copy() n = len(f) if not n: return FormalPowerSeries() if n <= 100: arr = [0] * (2 * n - 1) for i in range(n): for j in range(n): arr[i + j] += f[i] * f[j] arr[i + j] %= MOD return FormalPowerSeries(arr) z = 1 << (2 * n - 2).bit_length() f += [0] * (z - n) butterfly(f) for i in range(z): f[i] *= f[i] f[i] %= MOD butterfly_inv(f) f = f[:2 * n - 1] return FormalPowerSeries(f) def __lshift__(self, key): assert key >= 0 return FormalPowerSeries([0] * key + self.arr) def __rshift__(self, key): assert key >= 0 return self[key:] def __invert__(self): assert self[0] != 0 n = len(self) r = pow(self[0], MOD - 2, MOD) m = 1 res = FormalPowerSeries([r]) while m < n: f = [0] * (2 * m) g = [0] * (2 * m) for i in range(2 * m): f[i] = self[i] for i in range(m): g[i] = res[i] butterfly(f) butterfly(g) for i in range(2 * m): f[i] *= g[i] f[i] %= MOD butterfly_inv(f) for i in range(m): f[i] = 0 butterfly(f) for i in range(2 * m): f[i] *= g[i] f[i] %= MOD butterfly_inv(f) for i in range(m, 2 * m): res[i] -= f[i] m <<= 1 return res.resize(n) def __truediv__(self, other): if other.__class__ == FormalPowerSeries: return self * ~other else: return self * pow(other, MOD - 2, MOD) def __rtruediv__(self, other): return other * ~self def differentiate(self): n = len(self) arr = [0] * n for i in range(1, n): arr[i - 1] = self[i] * i % MOD return FormalPowerSeries(arr) def integrate(self): n = len(self) arr = [0] * n for i in range(n - 1): arr[i + 1] = self[i] * pow(i + 1, MOD - 2, MOD) % MOD return FormalPowerSeries(arr) def log(self): assert self[0] == 1 n = len(self) return (self.differentiate() / self).integrate().resize(n) def __floordiv__(self, other): if other.__class__ == FormalPowerSeries: n = len(self) m = len(other) if n < m: return FormalPowerSeries() l = n - m + 1 if m <= 100: arr = [0] * l inv = pow(other[m - 1], MOD - 2, MOD) tmp = self[::-1] for i in range(l): arr[i] = tmp[i] * inv % MOD for j in range(m): tmp[i + j] -= other[m - j - 1] * arr[i] tmp[i + j] %= MOD return FormalPowerSeries(arr[::-1]) res = (self[~l:][::-1] * ~(other[::-1].resize(l))).resize(l)[::-1] return res else: return self * pow(other, MOD - 2, MOD) def __rfloordiv__(self, other): return other * ~self def __mod__(self, other): n = len(self) m = len(other) if n < m: return FormalPowerSeries(self.arr) res = self[:m - 1] - ((self // other) * other)[:m - 1] return res def multipoint_evaluation(self, xs): n = len(xs) sz = 1 << (n - 1).bit_length() g = [FormalPowerSeries([1]) for _ in range(2 * sz)] for i in range(n): g[i + sz] = FormalPowerSeries([-xs[i], 1]) for i in range(1, sz)[::-1]: g[i] = g[2 * i] * g[2 * i + 1] g[1] = self % g[1] for i in range(2, 2 * sz): g[i] = g[i >> 1] % g[i] res = [g[i + sz][0] for i in range(n)] return res def polynomial_interpolation(xs, ys): assert len(xs) == len(ys) n = len(xs) sz = 1 << (n - 1).bit_length() f = [FormalPowerSeries([1]) for _ in range(2 * sz)] for i in range(n): f[i + sz] = FormalPowerSeries([-xs[i], 1]) for i in range(1, sz)[::-1]: f[i] = f[2 * i] * f[2 * i + 1] g = [FormalPowerSeries([0])] * (2 * sz) g[1] = f[1].differentiate() % f[1] for i in range(2, n + sz): g[i] = g[i >> 1] % f[i] for i in range(n): g[i + sz] = FormalPowerSeries([ys[i] * pow(g[i + sz][0], MOD - 2, MOD) % MOD]) for i in range(1, sz)[::-1]: g[i] = g[2 * i] * f[2 * i + 1] + g[2 * i + 1] * f[2 * i] return g[1][:n] def berlekamp_massey(arr): if arr.__class__ == FormalPowerSeries: arr = arr.arr n = len(arr) b = [1] c = [1] l, m, p = 0, 0, 1 for i in range(n): m += 1 d = arr[i] for j in range(1, l + 1): d += c[j] * arr[i - j] d %= MOD if d == 0: continue t = c.copy() q = d * pow(p, MOD - 2, MOD) % MOD if len(c) < len(b) + m: c += [0] * (len(b) + m - len(c)) for j in range(len(b)): c[j + m] -= q * b[j] c[j + m] %= MOD if 2 * l <= i: b = t l, m, p = i + 1 - l, 0, d return c def linear_recurrence(arr, coeff, k): if arr.__class__ == FormalPowerSeries: arr = arr.arr d = len(arr) f = FormalPowerSeries(arr) q = FormalPowerSeries(coeff) p = (f * q).resize(d) while k: r = [-q[i] if i & 1 else q[i] for i in range(len(q))] + [0] * (d + 1 - len(q)) r = FormalPowerSeries(r) p *= r q *= r p = p[(k & 1)::2] q = q[::2] k >>= 1 return p[0] % MOD class SegmentTree: def __init__(self, init_val, segfunc, ide_ele): n = len(init_val) self.segfunc = segfunc self.ide_ele = ide_ele self.num = 1 << (n - 1).bit_length() self.tree = [ide_ele] * 2 * self.num self.size = n for i in range(n): self.tree[self.num + i] = init_val[i] for i in range(self.num - 1, 0, -1): self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1]) mod = 998244353 N = 2*10**5 g1 = [1]*(N+1) g2 = [1]*(N+1) inverse = [1]*(N+1) for i in range( 2, N + 1 ): g1[i]=( ( g1[i-1] * i ) % mod ) inverse[i]=( ( -inverse[mod % i] * (mod//i) ) % mod ) g2[i]=( (g2[i-1] * inverse[i]) % mod ) inverse[0]=0 import sys input = sys.stdin.buffer.readline M,N = map(int,input().split()) A = list(map(int,input().split())) cnt = [0] * (M) for a in A: cnt[a-1] += 1 A = [a for a in cnt if a!=0] m = max(A) from collections import deque fs = deque([FormalPowerSeries([-a,1]) for a in A]) while len(fs) > 1: f = fs.popleft() g = fs.popleft() h = f * g fs.append(h)