#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433;

template <class T> vector<T> make_v(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto make_v(size_t N,T... t){return vector<decltype(make_v(t...))>(N,make_v(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

set<string> st;
void dfs(string s){
    if(!st.insert(s).second) return;
    for(int i = 0; i + 1 < s.size(); ++i){
        if((s[i]=='a' && s[i+1]=='b') || (s[i]=='b' && s[i+1]=='a')) {
           dfs(s.substr(0,i)+"cc" + s.substr(i+2,2));
        }
        if((s[i]=='b' && s[i+1]=='c') || (s[i]=='c' && s[i+1]=='b')) {
           dfs(s.substr(0,i)+"aa" + s.substr(i+2,2));
        }
        if((s[i]=='c' && s[i+1]=='a') || (s[i]=='a' && s[i+1]=='c')) {
           dfs(s.substr(0,i)+"bb" + s.substr(i+2,2));
        }
    }
}

int main() {
    string S; cin >> S;
    int N = S.size();
    int flg = 1;
    for(int i = 0; i + 1 < N; ++i) if(S[i] != S[i+1]) flg = 0;
    corner(flg,1);
    if(N<=3){
        dfs(S);
        corner(1,st.size());
    }
    auto dp1 = make_v(N,3,3,0LL);
    auto dp2 = make_v(N,3,3,0LL);
    
    for(int i = 0; i < 3; ++i){
        for(int j = 0; j < 3; ++j){
            for(int k = 0; k < 3; ++k){
                if(i!=j&&j!=k)dp1[2][(i+j+k)%3][k]++;
                else dp2[2][(i+j+k)%3][k]++;
            }
        }
    }

    for(int n = 2; n + 1 < N; ++n){
        for(int i = 0; i < 3; ++i){
            for(int j = 0; j < 3; ++j){
                for(int k = 0; k < 3; ++k){
                   if(i==j) (dp2[n+1][(k+i)%3][i] += dp1[n][k][j]) %= MOD2;
                   if(i!=j) (dp1[n+1][(k+i)%3][i] += dp1[n][k][j]) %= MOD2;
                   (dp2[n+1][(k+i)%3][i] += dp2[n][k][j]) %= MOD2;
                }
            }
        }
    }
    int mod = 0;
    for(int i = 0; i < N; ++i) mod += (S[i]-'a');
    ll ans = 1;
    for(int i = 0; i + 1 < N; ++i) if(S[i] == S[i+1]) ans = 0;
    for(int i = 0; i < 3; ++i) ans += dp2[N-1][mod%3][i];
    cout << ans % MOD2 << endl;
}


Measured memory_bytes: 78596