#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
//using mint = modint1000000007;
typedef long long ll;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> T;
template<typename T>bool chmax(T& a, const T& b) { if (a < b) { a = b;return true; } else { return false; } }
template<typename T>bool chmin(T& a, const T& b) { if (a > b) { a = b;return true; } else { return false; } }
template<class... Args> void dbg(Args&&... args) { ((cout << args << ' '), ...);cout << '\n'; }

const int di[] = { -1,0,1,0 };
const int dj[] = { 0,-1,0,1 };
const long long INF = 6000000000000000000;
const int inf = 1001001001;

// AtCoder の modint を使う
// MAXはnCkのnのmax
const int MAX = 510000;
mint fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    const int MOD = mint::mod();
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++) {
        fac[i] = fac[i - 1] * i;
        inv[i] = MOD - inv[MOD % i] * (MOD / i);
        finv[i] = finv[i - 1] * inv[i];
    }
}

// 二項係数計算
mint COM(int n, int k) {
    if (n < k)       return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * finv[k] * finv[n - k];
}

// main関数の中にCOMinit();を呼び出す
// 計算例
// COM(100000, 50000).val()

int main(void) {
    COMinit();
    string s; cin >> s;
    int n = s.size();
    vector<int> c;
    int cnt = 0;
    mint ans = 0;
    for (int i = 0; i < n; i++) {
        if (s[i] == 'M')cnt++;
        else {
            c.push_back(cnt);
            cnt = 0;
            ans += 1;
        }
    }

    int sum = 0;
    for (auto x : c) {
        sum += x;
        mint y = ((mint)(3)).pow(sum);
        ans += y - 1;
    }
    cout << ans.val() << "\n";
}