// Template #include #define rep_override(x, y, z, name, ...) name #define rep2(i, n) for (int i = 0; i < (int)(n); ++i) #define rep3(i, l, r) for (int i = (int)(l); i < (int)(r); ++i) #define rep(...) rep_override(__VA_ARGS__, rep3, rep2)(__VA_ARGS__) #define per(i, n) for (int i = (int)(n) - 1; i >= 0; --i) #define all(x) (x).begin(), (x).end() using namespace std; using ll = long long; constexpr int inf = 1001001001; constexpr ll INF = 3003003003003003003; template inline bool chmin(T& x, const T& y) {if (x > y) {x = y; return 1;} return 0;} template inline bool chmax(T& x, const T& y) {if (x < y) {x = y; return 1;} return 0;} struct IOSET {IOSET() {cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(10);}} ioset; // Number-Theoretical Transform // for example, (998244353, 31), (1012924417, 198), (1811939329, 136) template struct NumberTheoreticalTransform { vector zeta, inv_zeta; NumberTheoreticalTransform() { size_t exponents = 0; int tmp = mod - 1; while (not (tmp & 1)) { tmp >>= 1; ++exponents; } zeta.resize(exponents + 1); inv_zeta.resize(exponents + 1); zeta[exponents] = base; inv_zeta[exponents] = mod_pow(base, mod - 2); for (size_t i = exponents; i > 0; --i) { zeta[i - 1] = zeta[i] * zeta[i] % mod; inv_zeta[i - 1] = inv_zeta[i] * inv_zeta[i] % mod; } } ll mod_pow(ll x, ll y) { if (not y) return 1; ll a = mod_pow(x, y >> 1); if (y & 1) return a * a % mod * x % mod; return a * a % mod; } inline ll add(ll x, ll y) { if ((x += y) >= mod) x -= mod; return x; } void dft(vector &a, size_t exponents) { size_t m = 1 << exponents, now_e = exponents; while (m > 1) { for (size_t i = 0; i < a.size() / m; ++i) { ll now = 1; for (size_t j = 0; j < m / 2; ++j) { ll l = a[m * i + j]; ll r = a[m * i + j + m / 2]; a[m * i + j] = add(l, r); a[m * i + j + m / 2] = add(l, mod - r) * now % mod; now = now * zeta[now_e] % mod; } } m >>= 1; --now_e; } } void idft(vector &a, size_t exponents) { size_t m = 2, now_e = 1; while (m <= a.size()) { for (size_t i = 0; i < a.size() / m; ++i) { ll now = 1; for (size_t j = 0; j < m / 2; ++j) { ll l = a[m * i + j]; ll r = a[m * i + j + m / 2] * now % mod; a[m * i + j] = add(l, r); a[m * i + j + m / 2] = add(l, mod - r); now = now * inv_zeta[now_e] % mod; } } m <<= 1; ++now_e; } } vector multiply(vector f, vector g) { size_t siz = 1, exp = 0; while (siz < f.size() + g.size()) { siz *= 2; ++exp; } vector nf(siz, 0), ng(siz, 0); for (size_t i = 0; i < f.size(); ++i) nf[i] = f[i]; for (size_t i = 0; i < g.size(); ++i) ng[i] = g[i]; dft(nf, exp); dft(ng, exp); for (size_t i = 0; i < siz; ++i) nf[i] = nf[i] * ng[i] % mod; idft(nf, exp); ll inv = mod_pow(siz, mod - 2); for (size_t i = 0; i < siz; ++i) nf[i] = nf[i] * inv % mod; return nf; } }; // Main constexpr int MOD = 998244353, ROOT = 31; int main() { NumberTheoreticalTransform ntt; string s; cin >> s; vector cnt(26, 0); for (char c: s) ++cnt[c - 'a']; // sort(all(cnt)); vector fact(s.size() + 1), inv_fact(s.size() + 1); fact[0] = 1; rep(i, s.size()) fact[i + 1] = fact[i] * (i + 1) % MOD; inv_fact[s.size()] = ntt.mod_pow(fact[s.size()], MOD - 2); per(i, s.size()) inv_fact[i] = inv_fact[i + 1] * (i + 1) % MOD; vector dp(s.size() + 1, 0); dp[0] = 1; rep(i, 26) { vector f(s.size() + 1), g(cnt[i] + 1); rep(j, s.size() + 1) f[j] = dp[j] * inv_fact[j] % MOD; rep(j, cnt[i] + 1) g[j] = inv_fact[j] % MOD; vector m = ntt.multiply(f, g); rep(i, s.size() + 1) dp[i] = m[i] * fact[i] % MOD; } ll ans = 0; rep(i, 1, s.size() + 1) ans += dp[i]; ans %= MOD; cout << ans << "\n"; return 0; }