#include //#include //#pragma GCC optimize("Ofast") using namespace std; #define reps(i,s,n) for(int i = s; i < n; i++) #define rep(i,n) reps(i,0,n) #define Rreps(i,n,e) for(int i = n - 1; i >= e; --i) #define Rrep(i,n) Rreps(i,n,0) #define ALL(a) a.begin(), a.end() #define fi first #define se second typedef long long ll; typedef vector vec; typedef vector mat; ll N,M,H,W,Q,K,A,B; string S; typedef pair P; const ll INF = (1LL<<58); class mint{ public: ll x; static unsigned long long mod; static unsigned long long mod_plus; mint(){x = 0;} mint(ll _x) : x((_x < 0 ? ((_x += mod_plus) < 0 ? _x + mod_plus : _x) : _x)%mod){} /*mint& operator=(const ll &a){ x = a; return *this; }*/ mint operator-(){ return x == 0 ? 0 : mod - x; } mint& operator+=(const mint& a){ if((x += a.x) >= mod) x -= mod; return *this; } mint operator+(const mint& a) const{ mint res(*this); return res += a; } mint& operator-=(const mint& a){ if((x -= a.x) < 0) x += mod; return *this; } mint operator-(const mint& a) const{ mint res(*this); return res -= a; } mint& operator*=(const mint& a){ (x *= a.x)%=mod; return *this; } /*mint& operator*=(const ll& a){ mint temp(a); return *this *= temp; }*/ mint operator*(const mint& a) const{ mint res(*this); return res *= a; } /*mint operator*(const ll& a) const{ mint res(*this); return res *= a; }*/ mint pow(unsigned long long pw) const{ mint res(1), comp(*this); while(pw){ if(pw&1) res *= comp; comp *= comp; pw >>= 1; } return res; } //以下、modが素数のときのみ mint inv() const{ mint res(*this); return res.pow(mod - 2); } mint& operator/=(const mint &a){ (x *= a.inv().x)%=mod; return *this; } mint operator/(const mint &a) const{ mint res(*this); return res /= a; } }; ostream& operator<<(ostream& os, const mint& a){ os << a.x; return os; } unsigned long long mint::mod = 998244353; unsigned long long mint::mod_plus = (LLONG_MAX / mint::mod) * mint::mod; using vm = vector; class NTT{ const int root; void make_root_pow(int n, vm &root_pow){ root_pow.resize(n + 1); mint new_root = mint(root).pow((mint::mod - 1) / n); root_pow[0].x = 1; rep(i,n){ root_pow[i + 1] = root_pow[i] * new_root; } } void make_bit_reverse(int n, vector &v){ v.resize(n); rep(i,n) v[i] = i; for(int i = 1; (1<> i; for(int j = l; j < r; ++j){ int temp = v[j - l] + plus; if(j < temp) swap(v[j], v[temp]); } } } void dft(int n, vm &f, bool inv, vm &root_pow, vector &id){ vm g(n); rep(i,n) g[i] = f[id[i]]; swap(f, g); for(int l = n / 2, len = 1; l >= 1; l /= 2, len *= 2){ for(int i = 0; i < n; i += len * 2){ rep(j, len){ mint z = inv ? root_pow[n - l * j] : root_pow[l * j]; g[i + j] = f[i + j] + (z * f[i + len + j]); g[i + len + j] = f[i + j] - (z * f[i + len + j]); } } swap(f, g); } if(inv) { mint n_inv = mint(n).inv(); rep(i, n) f[i] *= n_inv; } } public: NTT(int _x = 3) : root(_x){} vm convolution(vm &a, vm &b){ int sz = a.size() + b.size() - 1, n = 1; while(sz > n) n *= 2; vm g(n, 0), h(n, 0), root_pow(n + 1, 1), gh(n); vector id(n); rep(i, (int)a.size()) g[i] += a[i]; rep(i, (int)b.size()) h[i] += b[i]; make_root_pow(n, root_pow); make_bit_reverse(n, id); dft(n, g, false, root_pow, id); dft(n, h, false, root_pow, id); rep(i, n) gh[i] = g[i] * h[i]; dft(n, gh, true, root_pow, id); gh.resize(sz); return gh; } }; const ll MAX_N = ll(4e+5) + 10; vm fact(MAX_N, mint(1)), fact_inv(MAX_N, mint(1)); void makefact(){ reps(i,2,MAX_N) { fact[i] = fact[i-1] * mint(i); fact_inv[i] = fact[i].inv(); } } int main() { makefact(); cin>>S; N = S.size(); vec num(26, 0); for(char c : S) ++num[c - 'a']; sort(ALL(num)); NTT ntt; vm dp(1, 0), temp; dp[0] = 1; int sum = 0; rep(i, 26){ sum += num[i]; temp.resize(num[i] + 1); copy(fact_inv.begin(), fact_inv.begin() + num[i] + 1, temp.begin()); dp = ntt.convolution(dp, temp); dp.resize(sum + 1); } mint ans(0); rep(i, N) ans += fact[i + 1] * dp[i + 1]; cout<