#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <cassert>
#include <random>
#include <iomanip>
#include <bitset>
#define FOR(i, n, m) for(ll i = n; i < (int)m; i++)
#define REP(i, n) FOR(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define pb push_back
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
constexpr ll inf = 1000000000;
constexpr ll mod = 998244353;
constexpr long double eps = 1e-15;
 
template<typename T1, typename T2>
ostream& operator<<(ostream& os, pair<T1, T2> p) {
    os << to_string(p.first) << " " << to_string(p.second);
    return os;
}
template<typename T>
ostream& operator<<(ostream& os, vector<T>& v) {
    REP(i, v.size()) {
        if(i) os << " ";
        os << to_string(v[i]);
    }
    return os;
}
 
struct modint {
    ll n;
public:
    modint(const ll n = 0) : n((n % mod + mod) % mod) {}
    static modint pow(modint a, int m) {
        modint r = 1;
        while(m > 0) {
            if(m & 1) { r *= a; }
            a = (a * a); m /= 2;
        }
        return r;
    }
    modint &operator++() { *this += 1; return *this; }
    modint &operator--() { *this -= 1; return *this; }
    modint operator++(int) { modint ret = *this; *this += 1; return ret; }
    modint operator--(int) { modint ret = *this; *this -= 1; return ret; }
    modint operator~() const { return (this -> pow(n, mod - 2)); } // inverse
    friend bool operator==(const modint& lhs, const modint& rhs) {
        return lhs.n == rhs.n;
    }
    friend bool operator<(const modint& lhs, const modint& rhs) {
        return lhs.n < rhs.n;
    }
    friend bool operator>(const modint& lhs, const modint& rhs) {
        return lhs.n > rhs.n;
    }
    friend modint &operator+=(modint& lhs, const modint& rhs) {
        lhs.n += rhs.n;
        if (lhs.n >= mod) lhs.n -= mod;
        return lhs;
    }
    friend modint &operator-=(modint& lhs, const modint& rhs) {
        lhs.n -= rhs.n;
        if (lhs.n < 0) lhs.n += mod;
        return lhs;
    }
    friend modint &operator*=(modint& lhs, const modint& rhs) {
        lhs.n = (lhs.n * rhs.n) % mod;
        return lhs;
    }
    friend modint &operator/=(modint& lhs, const modint& rhs) {
        lhs.n = (lhs.n * (~rhs).n) % mod;
        return lhs;
    }
    friend modint operator+(const modint& lhs, const modint& rhs) {
        return modint(lhs.n + rhs.n);
    }
    friend modint operator-(const modint& lhs, const modint& rhs) {
        return modint(lhs.n - rhs.n);
    }
    friend modint operator*(const modint& lhs, const modint& rhs) {
        return modint(lhs.n * rhs.n);
    }
    friend modint operator/(const modint& lhs, const modint& rhs) {
        return modint(lhs.n * (~rhs).n);
    }
};
istream& operator>>(istream& is, modint m) { is >> m.n; return is; }
ostream& operator<<(ostream& os, modint m) { os << m.n; return os; }
 
#define MAX_N 3030303
long long extgcd(long long a, long long b, long long& x, long long& y) {
    long long d = a;
    if (b != 0) {
        d = extgcd(b, a % b, y, x);
        y -= (a / b) * x;
    } else {
        x = 1; y = 0;
    }
    return d;
}
long long mod_inverse(long long a, long long m) {
    long long x, y;
    if(extgcd(a, m, x, y) == 1) return (m + x % m) % m;
    else return -1;
}
vector<long long> fact(MAX_N+1, inf);
long long mod_fact(long long n, long long& e) {
    if(fact[0] == inf) {
        fact[0]=1;
        if(MAX_N != 0) fact[1]=1;
        for(ll i = 2; i <= MAX_N; ++i) {
            fact[i] = (fact[i-1] * i) % mod;
        }
    }
    e = 0;
    if(n == 0) return 1;
    long long res = mod_fact(n / mod, e);
    e += n / mod;
    if((n / mod) % 2 != 0) return (res * (mod - fact[n % mod])) % mod;
    return (res * fact[n % mod]) % mod;
}
// return nCk
long long mod_comb(long long n, long long k) {
    if(n < 0 || k < 0 || n < k) return 0;
    long long e1, e2, e3;
    long long a1 = mod_fact(n, e1), a2 = mod_fact(k, e2), a3 = mod_fact(n - k, e3);
    if(e1 > e2 + e3) return 0;
    return (a1 * mod_inverse((a2 * a3) % mod, mod)) % mod;
}
 
using mi = modint;
 
mi mod_pow(mi a, ll n) {
    mi ret = 1;
    mi tmp = a;
    while(n > 0) {
        if(n % 2) ret *= tmp;
        tmp = tmp * tmp;
        n /= 2;
    }
    return ret;
}
 
ll gcd(ll a, ll b) {
    if (b == 0) return a;
    return gcd(b, a % b);
}

void dfs(vector<int> v, set<vector<int>>& st) {
    st.insert(v);
    REP(i, (int)v.size() - 1) {
        if(v[i] == v[i + 1]) continue;
        int a = v[i], b = v[i + 1];
        v[i] = 3 ^ a ^ b;
        v[i + 1] = 3 ^ a ^ b;
        if(!st.count(v)) dfs(v, st);
        v[i] = a;
        v[i + 1] = b;
    }
    return;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    string s;
    cin >> s;
    int n = (int)s.size();
    vector<int> v(n);
    REP(i, n) {
        if(s[i] == 'a') v[i] = 0;
        if(s[i] == 'b') v[i] = 1;
        if(s[i] == 'c') v[i] = 2;
    }
    if(n <= 4) {
        set<vector<int>> st;
        dfs(v, st);
        cout << (int)st.size() << endl;
        return 0;
    }
    vector<vector<vector<int>>> dp(n, vector<vector<int>>(3, vector<int>(3, 0)));
    dp[0][0][0] = dp[0][1][1] = dp[0][2][2] = 1;
    FOR(i, 1, n) REP(j, 3) REP(k, 3) {
        dp[i][j][k] += dp[i - 1][(j + (3 - k)) % 3][0];
        dp[i][j][k] += dp[i - 1][(j + (3 - k)) % 3][1];
        dp[i][j][k] += dp[i - 1][(j + (3 - k)) % 3][2];
        dp[i][j][k] -= dp[i - 1][(j + (3 - k)) % 3][k];
        dp[i][j][k] %= mod;
    }
    bool b1 = true, b2 = true;
    REP(i, n - 1) if(v[i] == v[i + 1]) b2 = false;
    FOR(i, 1, n) if(v[i] != v[0]) b1 = false;
    if(b1) {
        cout << 1 << endl;
        return 0;
    }
    int sum = 0;
    REP(i, n) sum += v[i];
    sum %= 3;
    mi ans = mod_pow(3, n - 1) - dp[n - 1][sum][0]
             - dp[n - 1][sum][1] - dp[n - 1][sum][2];
    if(b2) ans++;
    cout << ans << endl;
    return 0;
}


Measured memory_bytes: 64020