def solve():
    s = list(input())

    MOD = 998244353
    threepows = [1]
    for i in range(1, len(s)+1):
        threepows.append((threepows[-1]*3) % MOD)


    mc = 0
    ans = 0
    for i in range(len(s)):
        if s[i] == 'M':
            mc += 1
        if s[i] == 'A':
            ans += threepows[mc]
            ans %= MOD
    print(ans % MOD)

if __name__ == "__main__":
    solve()