#pragma GCC target("avx2")
#pragma GCC optimize("unroll-loops")

#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define ALL(x) (x).begin(), (x).end()
#define PC(x) __builtin_popcount(x)
#define PCL(x) __builtin_popcountll(x)

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
struct edge {
    int to, cost, id;
};
const double PI = 3.14159265358979323846;
const double PI2 = PI * 2.0;
const double EPS = 1E-09;
const ll MOD = 998244353;
const ll INFL = 1E18;
const int INFI = 1E09;
const int MAX_N = 3E+05;

ll dx[4] = { 0, -1, 0, 1 }, dy[4] = { 1, 0, -1, 0 };

ll N;
ll modfac[MAX_N + 1];
ll modfacinv[MAX_N + 1];
string S;

ll modPow(ll x, ll a)
{
    ll ans = 1;
    while (a > 0) {
        if (a & 1) {
            ans = (ans * x) % MOD;
        }
        x = (x * x) % MOD;
        a >>= 1;
    }
    return ans;
}

// (n!)^-1を求める
void modfactorInv(ll n)
{
    ll p = n - 1;
    while (p >= 0) {
        modfacinv[p] = ((p + 1) * modfacinv[p + 1]) % MOD;
        p--;
    }
}

// n!を求める
ll modfactor(ll n)
{
    modfac[0] = 1;
    ll p = 1;
    while (p <= n) {
        // cout << p << "\n";
        modfac[p] = (p * modfac[p - 1]) % MOD;
        p++;
    }
    modfacinv[n] = modPow(modfac[n], MOD - 2);
    modfactorInv(n);
    return modfac[n];
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> S;

    modfactor(N);
    ll x = 0;
    for (auto c : S) {
        if (c == 'A' || c == 'B')
            x++;
    }

    // for (int i = 0; i < N; i++) {
    //     for (int j = 0; j < N; j++) {
    //         cout << "i = " << i << ", j = " << j << ", dp = " << dp[i][j] << "\n";
    //     }
    // }

    cout << modfac[N] * modfacinv[N - x] % MOD * modfacinv[x] % MOD << "\n";

    return 0;
}