import std;

void main () {
    const long MOD = 998244353;
    string S = readln.chomp;

    // いや、数学かと思ったらギャグで横転

    long ans = 0;
    long count = 1;
    foreach (c; S) {
        if (c == 'M') {
            count *= 3;
            count %= MOD;
        }
        if (c == 'A') {
            ans += count;
        }
    }

    ans %= MOD;
    writeln(ans);
}

void read (T...) (string S, ref T args) {
    import std.conv : to;
    import std.array : split;
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}