using System; using System.Collections.Generic; using System.Linq; using System.IO; using System.Text; using System.Numerics; using System.Threading; using System.Runtime.CompilerServices; using System.Diagnostics; using static System.Math; using static System.Array; using static AtCoder.Cout; using static AtCoder.Tool; using static AtCoder.ModInt; namespace AtCoder { class AC { //const int MOD = 1000000007; const int MOD = 998244353; const int INF = int.MaxValue / 2; const long SINF = long.MaxValue / 3; const double EPS = 1e-8; static readonly int[] dI = { 0, 1, 0, -1, 1, -1, -1, 1 }; static readonly int[] dJ = { 1, 0, -1, 0, 1, 1, -1, -1 }; static void Main(string[] args) { //var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; Console.SetOut(sw); var th = new Thread(Run, 1 << 26); th.Start(); th.Join(); //Run(); Console.Out.Flush(); } static void Run() { int Testcase = 1; //Testcase = Cin.Int; for (var _ = 0; _ < Testcase; _++) Solve(); } static void Solve() { var S = Cin.Str; var c = new int[26]; for (var i = 0; i < S.Length; i++) c[S[i] - 'a']++; Sort(c); var P = new long[26][]; for(var i = 0; i < 26; i++) { P[i] = new long[c[i] + 1]; for (var j = 0; j <= c[i]; j++) P[i][j] = (1 / Fac(j)).value; } var ntt = new Math_NTT(998244353, 3); for (var i = 1; i < 26; i++) P[0] = ntt.Convolution_NTT(P[0], P[i]); ModInt ans = 0; //Out_Sep(P[0]); for (var L = 1; L <= S.Length; L++) ans += P[0][L] * Fac(L); OutL(ans.value); } public struct Edge { public int from; public int to; public long dist; public Edge(int t, long c) { from = -1; to = t; dist = c; } public Edge(int f, int t, long c) { from = f; to = t; dist = c; } } } public class Math_NTT { private long mod; private long root; public Math_NTT(long prime_mod, long premitive_root) { mod = prime_mod; root = premitive_root; } [MethodImpl(MethodImplOptions.AggressiveInlining)] long modpow(long x, long nn) => nn == 0 ? 1 : (nn % 2 == 0 ? modpow((x * x) % mod, nn / 2) : (x * modpow(x, nn - 1)) % mod); [MethodImpl(MethodImplOptions.AggressiveInlining)] long inverse(long x) => modpow(x, mod - 2); /*[MethodImpl(MethodImplOptions.AggressiveInlining)] public void NTT(ref long[] a, bool inv = false) { int n = a.Length; int h = 0; for (var i = 0; (1 << i) < n; i++) h++; //バタフライ演算準備 for (var i = 0; i < n; i++) { int j = 0; for (var k = 0; k < h; k++) j |= ((i >> k) & 1) << (h - 1 - k); //2進法表記が逆の数字とスワップする if (i < j) { var kep = a[i]; a[i] = a[j]; a[j] = kep; } } //バタフライ演算パート for (var b = 1; b < n; b <<= 1) { long W = modpow(root, (inv ? (mod - 1) - (mod - 1) / (b << 1) : (mod - 1) / (b << 1))); long z = 1; for (var j = 0; j < b; j++) { for (var k = 0; k < n; k += (b << 1)) { var s = a[k + j]; var t = (a[k + j + b] * z) % mod; a[k + j] = (s + t) % mod; a[k + j + b] = (s - t + mod) % mod; } z = (z * W) % mod; } } if (inv) { for (var i = 0; i < n; i++) a[i] = (a[i] * modpow(n, mod - 2)) % mod; } }*/ void NTT(ref long[] a, bool rev = false) { var n = (long)a.Length; if (n == 1) return; var b = new long[n]; var s = modpow(root, rev ? (mod - 1 - (mod - 1) / n) : (mod - 1) / n); var kp = Enumerable.Repeat((long)1, (int)(n / 2 + 1)).ToArray(); long i, j, k, l, r; for (i = 0; i < n / 2; ++i) kp[i + 1] = (kp[i] * s) % mod; for (i = 1, l = n / 2; i < n; i <<= 1, l >>= 1) { for (j = 0, r = 0; j < l; ++j, r += i) { for (k = 0, s = kp[i * j]; k < i; ++k) { var p = a[k + r]; var q = a[k + r + n / 2]; b[k + 2 * r] = (p + q) % mod; b[k + 2 * r + i] = ((p - q + mod) % mod * s) % mod; } } var t = a; a = b; b = t; } if (rev) { s = inverse(n); for (i = 0; i < n; ++i) a[i] = (a[i] * s) % mod; } } /*[MethodImpl(MethodImplOptions.AggressiveInlining)] public long[] Convolution_NTT(long[] a, long[] b) { int N = a.Length + b.Length - 1; int t = 1; while (t < N) t <<= 1; var nxa = new long[t]; var nxb = new long[t]; for (var i = 0; i < t; i++) { nxa[i] = i < a.Length ? a[i] : 0; nxb[i] = i < b.Length ? b[i] : 0; } NTT(ref nxa); NTT(ref nxb); for (var i = 0; i < t; i++) nxa[i] = (nxa[i] * nxb[i]) % mod; NTT(ref nxa, true); var ret = new long[N]; for (var i = 0; i < N; i++) ret[i] = nxa[i]; return ret; }*/ public long[] Convolution_NTT(long[] a, long[] b) { //memo: mod 998244353 => primitive_root = 3 // mod 924844033 => root = 5 int N = a.Length + b.Length - 1; int t = 1; while (t < N) t <<= 1; var nxa = new long[t]; var nxb = new long[t]; for (var i = 0; i < t; i++) { nxa[i] = i < a.Length ? a[i] : 0; nxb[i] = i < b.Length ? b[i] : 0; } NTT(ref nxa); NTT(ref nxb); for (var i = 0; i < t; i++) nxa[i] = (nxa[i] * nxb[i]) % mod; NTT(ref nxa, true); var ret = new long[N]; for (var i = 0; i < N; i++) ret[i] = nxa[i]; return ret; } } struct ModInt { public long value; //private const int MOD = 1000000007; private const int MOD = 998244353; public ModInt(long value) { this.value = value; } public static implicit operator ModInt(long a) { var ret = a % MOD; return new ModInt(ret < 0 ? (ret + MOD) : ret); } public static ModInt operator +(ModInt a, ModInt b) => (a.value + b.value); public static ModInt operator -(ModInt a, ModInt b) => (a.value - b.value); public static ModInt operator *(ModInt a, ModInt b) => (a.value * b.value); public static ModInt operator /(ModInt a, ModInt b) => a * Modpow(b, MOD - 2); public static ModInt operator <<(ModInt a, int n) => (a.value << n); public static ModInt operator >>(ModInt a, int n) => (a.value >> n); public static ModInt operator ++(ModInt a) => a.value + 1; public static ModInt operator --(ModInt a) => a.value - 1; [MethodImpl(MethodImplOptions.AggressiveInlining)] public static ModInt Modpow(ModInt a, long n) { var k = a; ModInt ret = 1; while (n > 0) { if ((n & 1) != 0) ret *= k; k *= k; n >>= 1; } return ret; } private static readonly List Factorials = new List() { 1 }; [MethodImpl(MethodImplOptions.AggressiveInlining)] public static ModInt Fac(long n) { for (var i = Factorials.Count(); i <= n; i++) { Factorials.Add((Factorials[i - 1] * i) % MOD); } return Factorials[(int)n]; } [MethodImpl(MethodImplOptions.AggressiveInlining)] public static ModInt nCr(long n, long r) { if (n < 0 || r < 0) return 0; return n < r ? 0 : Fac(n) / (Fac(r) * Fac(n - r)); } public static explicit operator int(ModInt a) => (int)a.value; } public class Rolling_Hash { const ulong m30 = (1UL << 30) - 1; const ulong m31 = (1UL << 31) - 1; const ulong MOD = (1UL << 61) - 1; const ulong Pl = (MOD << 1) << 1; private uint B; private string S; ulong[] hash; ulong[] pw; public Rolling_Hash(string str) { S = str; B = (uint)new Random().Next(1 << 12 + 1, int.MaxValue); int L = S.Length; hash = new ulong[L + 1]; pw = new ulong[L + 1]; hash[0] = 0; pw[0] = 1; for (var i = 0; i < L; i++) { hash[i + 1] = CalcMod(Mul(hash[i], B) + S[i]); pw[i + 1] = CalcMod(Mul(pw[i], B)); } } [MethodImpl(MethodImplOptions.AggressiveInlining)] public ulong GetHashValue(int idx) => hash[idx]; [MethodImpl(MethodImplOptions.AggressiveInlining)]//segment [l,r] public ulong Hash_fold(int l, int r) => CalcMod(Pl + hash[r + 1] - Mul(hash[l], pw[r - l + 1])); [MethodImpl(MethodImplOptions.AggressiveInlining)]//segment[start,start+len-1] public ulong Hash_sub(int start, int len) => CalcMod(Pl + hash[start + len] - Mul(hash[start], pw[len])); [MethodImpl(MethodImplOptions.AggressiveInlining)] public ulong[] GetHashArray() => hash; [MethodImpl(MethodImplOptions.AggressiveInlining)] ulong Mul(ulong a, ulong b) { ulong au = a >> 31; ulong ad = a & m31; ulong bu = b >> 31; ulong bd = b & m31; ulong mid = ad * bu + au * bd; ulong midu = mid >> 30; ulong midd = mid & m30; return au * bu * 2 + midu + (midd << 31) + ad * bd; } [MethodImpl(MethodImplOptions.AggressiveInlining)] ulong CalcMod(ulong x) { ulong xu = x >> 61; ulong xd = x & MOD; ulong res = xu + xd; if (res >= MOD) res -= MOD; return res; } } public class Priority_Queue { private List Q; private readonly Comparison Func_Compare; public Priority_Queue(Comparison comp) { Func_Compare = comp; Q = new List(); } private void PushHeap(List list, T item) { int n = list.Count(); list.Add(item); while (n != 0) { int pIndex = (n - 1) / 2; if (Func_Compare(list[n], list[pIndex]) < 0) { Swap(Q, n, pIndex); } else { break; } n = pIndex; } } private void PopHeap(List list) { int n = list.Count() - 1; list[0] = list[n]; list.RemoveAt(n); int cur = 0; int comp; while (2 * cur + 1 <= n - 1) { int c1 = 2 * cur + 1; int c2 = 2 * (cur + 1); if (c1 == n - 1) { comp = c1; } else { comp = Func_Compare(list[c1], list[c2]) < 0 ? c1 : c2; } if (Func_Compare(list[cur], list[comp]) > 0) { Swap(Q, cur, comp); } else { break; } cur = comp; } } private void Swap(List list, int a, int b) { T keep = list[a]; list[a] = list[b]; list[b] = keep; } public void Enqueue(T value) { PushHeap(Q, value); } public T Dequeue() { T ret = Q[0]; PopHeap(Q); return ret; } public T Peek() { return Q[0]; } public int Count() { return Q.Count(); } public bool Any() { return Q.Any(); } } public class SegmentTree { //1-indexed type int n; T[] Tree; Func f; T ex; int L; [MethodImpl(MethodImplOptions.AggressiveInlining)] public SegmentTree(int size, Func fun, T exvalue) { ex = exvalue; f = fun; n = 1; while (n < size) n <<= 1; Tree = new T[n << 1]; L = (n << 1) - 1; for (var i = 0; i <= L; i++) Tree[i] = ex; } [MethodImpl(MethodImplOptions.AggressiveInlining)] public SegmentTree(int size, Func fun, T exvalue, T[] initial) { ex = exvalue; n = 1; while (n < size) n <<= 1; f = fun; Tree = new T[n << 1]; L = (n << 1) - 1; for (var i = 0; i <= L; i++) Tree[i] = (n <= i && i <= n + initial.Length - 1) ? initial[i - n] : ex; } [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Set_All() { for (var i = n - 1; i >= 1; i--) Tree[i] = f(Tree[i << 1], Tree[(i << 1) | 1]); } [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Assign(int idx, T nxt) => Tree[idx + n] = nxt; [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Update(int idx) { int now = idx + n; while (now > 1) { now >>= 1; Tree[now] = f(Tree[now << 1], Tree[now << 1 | 1]); } } [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Query_Update(int idx, T nxt) { Assign(idx, nxt); Update(idx); } [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Query_Update_func(int idx, T y) { Assign(idx, f(Peek(idx), y)); Update(idx); } [MethodImpl(MethodImplOptions.AggressiveInlining)] public T Query_Fold(int l, int r) { int L = n + l; int R = n + r; T vL = ex, vR = ex; while (L < R) { if (L % 2 == 1) { vL = f(vL, Tree[L]); L++; } if (R % 2 == 1) { vR = f(Tree[R - 1], vR); R--; } L >>= 1; R >>= 1; } return f(vL, vR); } [MethodImpl(MethodImplOptions.AggressiveInlining)] public T Peek(int idx) => Tree[idx + n]; [MethodImpl(MethodImplOptions.AggressiveInlining)] public void Display(int len) { for (var i = 0; i < len; i++) Console.Write($"{Tree[i + n]} "); Console.WriteLine(); } } public class UnionFind { private int[] parent; private int[] rank; private int[] size; public UnionFind(int n) { parent = new int[n]; rank = new int[n]; size = new int[n]; for (var i = 0; i < n; i++) { parent[i] = i; rank[i] = 0; size[i] = 1; } } public int Root(int x) { return parent[x] == x ? x : parent[x] = Root(parent[x]); } public bool SameRoot(int x, int y) { return Root(x) == Root(y); } public void Unite(int x, int y) { x = Root(x); y = Root(y); if (x == y) { return; } if (rank[x] < rank[y]) { parent[x] = y; size[y] += size[x]; size[x] = 0; } else { parent[y] = x; if (rank[x] == rank[y]) { rank[x]++; } size[x] += size[y]; size[y] = 0; } } public int SizeOf(int x) { return size[Root(x)]; } } static class Cin { public static string[] ReadSplit => Console.ReadLine().Split(); public static int[] ReadSplitInt => ConvertAll(Console.ReadLine().Split(), int.Parse); public static long[] ReadSplitLong => ConvertAll(Console.ReadLine().Split(), long.Parse); public static double[] ReadSplit_Double => ConvertAll(Console.ReadLine().Split(), double.Parse); public static string Str => Console.ReadLine(); public static int Int => int.Parse(Console.ReadLine()); public static long Long => long.Parse(Console.ReadLine()); public static double Double => double.Parse(Console.ReadLine()); public static T Conv(string input) { if (typeof(T).Equals(typeof(ModInt))) { return (T)(dynamic)(long.Parse(input)); } return (T)Convert.ChangeType(input, typeof(T)); } public static void Input(out T a) => a = Conv(Console.ReadLine()); public static void Input(out T a, out U b) { var q = ReadSplit; a = Conv(q[0]); b = Conv(q[1]); } public static void Input(out T a, out U b, out V c) { var q = ReadSplit; a = Conv(q[0]); b = Conv(q[1]); c = Conv(q[2]); } public static void Input(out T a, out U b, out V c, out W d) { var q = ReadSplit; a = Conv(q[0]); b = Conv(q[1]); c = Conv(q[2]); d = Conv(q[3]); } public static void Input(out T a, out U b, out V c, out W d, out X e) { var q = ReadSplit; a = Conv(q[0]); b = Conv(q[1]); c = Conv(q[2]); d = Conv(q[3]); e = Conv(q[4]); } } static class Cout { public static void OutL(object s) => Console.WriteLine(s); public static void Out_Sep(IEnumerable s) => Console.WriteLine(string.Join(" ", s)); public static void Out_Sep(IEnumerable s, string sep) => Console.WriteLine(string.Join($"{sep}", s)); public static void Out_Sep(params object[] s) => Console.WriteLine(string.Join(" ", s)); public static void Out_One(object s) => Console.Write($"{s} "); public static void Out_One(object s, string sep) => Console.Write($"{s}{sep}"); public static void Endl() => Console.WriteLine(); } public static class Tool { static public void Initialize(ref T[] array, T initialvalue) { array = ConvertAll(array, x => initialvalue); } static public void Swap(ref T a, ref T b) { T keep = a; a = b; b = keep; } static public void Display(T[,] array2d, int n, int m) { for (var i = 0; i < n; i++) { for (var j = 0; j < m; j++) { Console.Write($"{array2d[i, j]} "); } Console.WriteLine(); } } static public long Gcd(long a, long b) { if (a == 0 || b == 0) return Max(a, b); return a % b == 0 ? b : Gcd(b, a % b); } static public long LPow(int a, int b) => (long)Pow(a, b); static public bool Bit(long x, int dig) => ((1L << dig) & x) != 0; static public int Sig(long a) => a == 0 ? 0 : (int)(a / Abs(a)); } }