#include <bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using mint = atcoder::modint998244353;

#define rep(i, l, r) for (int i = (int)(l); i < (int)(r); i++)
#define ll long long
#define all(x) (x).begin(), (x).end()
#define siz(x) (int)x.size()

const int inf = 1e9;
const ll INF = 4e18;

template<class T> bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

int main() {
    int N; string S; cin >> N >> S;
    int a = 0, c = 0;
    for (char x : S) {
        if (x == 'A' or x == 'B') a++;
        else c++;
    }
    mint ans = 1;
    rep(i, 1, a + c + 1) ans *= i;
    rep(i, 1, a + 1) ans /= i;
    rep(i, 1, c + 1) ans /= i;
    
    cout << ans.val() << endl;
}