#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <tuple>
#include <utility>
#include <vector>
#define ll long long
#define itn int
#define endl '\n'
#define co(ans) cout<<ans<<endl
#define COYE cout<<"YES"<<endl
#define COYe cout<<"Yes"<<endl
#define COye cout<<"yes"<<endl
#define CONO cout<<"NO"<<endl
#define CONo cout<<"No"<<endl
#define COno cout<<"no"<<endl
#define FORE(i,a) for(auto &i:a)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FFOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n)  FFOR(i,1,n)
#define PB push_back
#define MP make_pair
#define ALL(V) (V).begin(),(V).end()
#define SORT(V) sort((V).begin(),(V).end())
#define REVERSE(V) reverse((V).begin(),(V).end())
#define EACH(V,i) for(typeof((V).begin()) i=(V).begin();i!=(V).end();++i)
#define equals(a,b) (fabs((a)-(b))<EPS)
#define INF ((1LL<<62)-(1LL<<31))
#define EPS 1e-10
#define PI 3.141592653589793238
#define MOD 1000000007
#define MMOD 998244353
#define MAX 2010101
using namespace std;
using Edge=pair<ll,ll>;
using Graph=vector<vector<int>>;
inline int toInt(string s){int v;istringstream sin(s);sin>>v;return v;}
template<class T>inline string toString(T x){ostringstream sout;sout<<x;return sout.str();}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
typedef long long LL;
const int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

bool alleq(string &s) {
    for (int i = 1; i < s.size(); i++) if (s[0] != s[i]) return false;
    return true;
}

bool checkadj(string &s) {
    for (int i = 1; i < s.size(); i++) if (s[i-1] == s[i]) return true;
    return false;
}

const int M = 998244353;

long long modexp(int x, long long e, int m) {
    long long ans = 1, p = x % m;
    while (e > 0) {
        if (e % 2 != 0) ans = (ans * p) % m;
        p = (p * p) % m;
        e >>= 1;
    }
    return ans;
}

int bruteforce(string &s) {
    set<string> ss;
    ss.insert(s);
    queue<string> q;
    q.push(s);
    int ans = 0;
    while (!q.empty()) {
        string t = q.front();
        q.pop();
        ans++;
        for (int i = 1; i < t.size(); i++) {
            if (t[i-1] != t[i]) {
                char c = int('a') + 'b' + 'c' - t[i-1] - t[i];
                string u = t;
                u[i-1] = u[i] = c;
                if (ss.find(u) == ss.end()) {
                    ss.insert(u);
                    q.push(u);
                }
            }
        }
    }
    return ans;
}

int main() {
    string s; cin >> s;
    if (alleq(s)) {
        assert (bruteforce(s) == 1);
        cout << "1\n";
        return 0;
    }
    if (s.size() == 3 && s[0] != s[1] && s[1] != s[2] && s[2] != s[0]) {
        assert (bruteforce(s) == 3);
        cout << "3\n";
        return 0;
    }

    int dp[2][3][3] = {}, cur = 0, prev = 1;
    for (int j = 0; j < 3; j++) dp[prev][j][j] = 1;
    for (int i = 1; i < s.size(); i++) {
        memset(dp[cur], 0, sizeof(dp[cur]));
        for (int j = 0; j < 3; j++)
            for (int k = 0; k < 3; k++)
                for (int l = 0; l < 3; l++)
                    if (k != l) dp[cur][(j + l)%3][l] += dp[prev][j][k] % M;

        swap(prev, cur);
    }
    const int sum = accumulate(s.begin(), s.end(), 0) % 3;
    long long ans = modexp(3, s.size()-1, M);
    ans -= accumulate(dp[prev][sum], dp[prev][sum]+3, 0LL);
    if (!checkadj(s)) ans++;
    cout << (ans % M + M) % M << endl;
}

Measured memory_bytes: 4072