#include <bits/stdc++.h>

#if MYDEBUG
#include "lib/cp_debug.hpp"
#else
#define DBG(...) ;
#endif
#if __cplusplus <= 201402L
template <typename T>
T gcd(T a, T b) { return ((a % b == 0) ? b : gcd(b, a % b)); }
template <typename T>
T lcm(T a, T b) { return a / gcd(a, b) * b; }
#endif
using LL = long long;
constexpr LL LINF = 334ll << 53;
constexpr int INF = 15 << 26;
constexpr LL MOD = 998244353;

namespace Problem {
using namespace std;
template <long long Mod = MOD>
class Modint {
 public:
  long long v;

  Modint(const Modint &x) { v = x.v; }
  explicit Modint(int x) {
    if (x < 0 or Mod <= x) x %= Mod;
    if (x < 0) x += Mod;
    v = x;
  }
  explicit Modint(long long x) {
    if (x < 0 or Mod <= x) x %= Mod;
    if (x < 0) x += Mod;
    v = x;
  }
  explicit Modint(unsigned x) {
    if (Mod <= x) x %= Mod;
    v = x;
  }
  explicit Modint(unsigned long long x) {
    if (Mod <= x) x %= Mod;
    v = x;
  }
  template <typename T>
  explicit Modint(T x) {
    if (x < 0 or Mod <= x) x %= Mod;
    v = x;
  }
  Modint() : v(0) {}
  long long get() const { return v; }
  Modint mpow(Modint &n) const { return mpow(n.v); }
  Modint mpow(long long n) const {
    long long i = 1, p = v;
    Modint ret(1);
    while (i <= n) {
      if (i & n) ret *= p;
      i = (i << 1);
      p = (p * p) % Mod;
    }
    return ret;
  }
  Modint operator-() const { return (v ? Modint(Mod - v) : Modint(0)); }
  explicit operator int() const { return v; }
  explicit operator long long() const { return v; }
  Modint &operator+=(const Modint &a) {
    v = (v + a.v);
    if (v >= Mod) v -= Mod;
    return *this;
  }
  Modint &operator-=(const Modint &a) {
    v = (v - a.v);
    if (v < 0) v += Mod;
    return *this;
  }
  Modint &operator*=(const Modint &a) {
    v = (v * a.v) % Mod;
    return *this;
  }
  Modint &operator/=(const Modint &a) {
    v = (v * a.mpow(Mod - 2).v) % Mod;
    return *this;
  }
  template <class T>
  Modint &operator+=(const T &a) {
    v = (v + Modint(a).v);
    if (v >= Mod) v -= Mod;
    return *this;
  }
  template <class T>
  Modint &operator-=(const T &a) {
    v = (v - Modint(a).v);
    if (v < 0) v += Mod;
    return *this;
  }
  template <class T>
  Modint &operator*=(const T &a) {
    v = (v * Modint(a).v) % Mod;
    return *this;
  }
  template <class T>
  Modint &operator/=(const T &a) {
    v = (v * Modint(a).mpow(Mod - 2).v) % Mod;
    return *this;
  }
  friend Modint operator+(const Modint &a, const Modint &b) {
    return Modint(a) += b;
  }
  friend Modint operator-(const Modint &a, const Modint &b) {
    return Modint(a) -= b;
  }
  friend Modint operator*(const Modint &a, const Modint &b) {
    return Modint(a) *= b;
  }
  friend Modint operator/(const Modint &a, const Modint &b) {
    return Modint(a) /= b;
  }
  template <class T, class U>
  friend Modint operator+(const T &a, const U &b) {
    return Modint(a) += Modint(b);
  }
  template <class T, class U>
  friend Modint operator-(const T &a, const U &b) {
    return Modint(a) -= Modint(b);
  }
  template <class T, class U>
  friend Modint operator*(const T &a, const U &b) {
    return Modint(a) *= Modint(b);
  }
  template <class T, class U>
  friend Modint operator/(const T &a, const U &b) {
    return Modint(a) /= Modint(b);
  }
};

template <long long M>
ostream &operator<<(ostream &os, const Modint<M> m) {
  return os << m.v;
}
class Solver {
 public:
  string s;
  int n;
  Solver(string s) : s(s), n(s.length()){};
  bool isValid(string &s) {
    for (int i = 0; i < n - 1; ++i) {
      if (s[i] == s[i + 1]) return false;
    }
    return true;
  }
  void solve() {
    auto s2 = s;
    sort(s2.begin(), s2.end());
    s2.erase(unique(s2.begin(), s2.end()), s2.end());
    if (s2.size() == 1) {
      cout << 1 << endl;
      return;
    }
    if (n <= 3) {
      set<string> S;
      queue<string> Q;
      Q.push(s);
      S.insert(s);
      string p = "acb";
      while (!Q.empty()) {
        auto now = Q.front();
        Q.pop();
        for (int i = 0; i < n - 1; ++i) {
          auto nxt = now;
          if (nxt[i] != nxt[i + 1]) {
            nxt[i] = nxt[i + 1] = p[(nxt[i] - 'a' + nxt[i + 1] - 'a') % 3];
          }
          if (S.count(nxt) == 0) {
            Q.push(nxt);
            S.insert(nxt);
          }
        }
      }
      cout << S.size() << endl;
      return;
    }
    vector<vector<vector<Modint<>>>> dp(n + 1, vector<vector<Modint<>>>(3, vector<Modint<>>(3)));
    for (int i = 0; i < 3; ++i) {
      dp[1][i][i] = Modint<>(1);
    }
    for (int i = 2; i <= n; ++i) {
      for (int j = 0; j < 3; ++j) {
        for (int k = 0; k < 3; ++k) {
          for (int l = 0; l < 3; ++l) {
            if (j == l) continue;
            dp[i][l][(k + l) % 3] += dp[i - 1][j][k];
          }
        }
      }
    }
    int t = 0;
    for (int i = 0; i < n; ++i) {
      t = (t + s[i] - 'a') % 3;
    }
    Modint<> ans = Modint<>(3).mpow(n - 1) + isValid(s);
    for (int i = 0; i < 3; ++i) {
      ans -= dp[n][i][t];
    }
    cout << ans << endl;
  }
};
}  // namespace Problem

int main() {
  std::cin.tie(0);
  std::ios_base::sync_with_stdio(false);
  // std::cout << std::fixed << std::setprecision(12);
  std::string s;
  std::cin >> s;

  Problem::Solver sol(s);
  sol.solve();
  return 0;
}


Measured memory_bytes: 41748