import java.io.*; import java.util.*; import java.util.stream.*; public class Main { static final int MOD = 998244353; public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); int ab = 0; int cd = 0; for (char c : sc.next().toCharArray()) { if (c == 'A' || c == 'B') { ab++; } else { cd++; } } long ans = fact(n) * pow(fact(ab), MOD - 2) % MOD * pow(fact(cd), MOD - 2) % MOD; System.out.println(ans); } static long pow(long x, int p) { if (p == 0) { return 1; } else if (p % 2 == 0) { return pow(x * x % MOD, p / 2); } else { return pow(x, p - 1) * x % MOD; } } static long fact(int x) { long ans = 1; for (int i = 2; i <= x; i++) { ans *= i; ans %= MOD; } return ans; } } class Utilities { static String arrayToLineString(Object[] arr) { return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n")); } static String arrayToLineString(int[] arr) { return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new)); } } class Scanner { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); StringTokenizer st = new StringTokenizer(""); StringBuilder sb = new StringBuilder(); public Scanner() throws Exception { } public int nextInt() throws Exception { return Integer.parseInt(next()); } public long nextLong() throws Exception { return Long.parseLong(next()); } public double nextDouble() throws Exception { return Double.parseDouble(next()); } public int[] nextIntArray() throws Exception { return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray(); } public String next() throws Exception { while (!st.hasMoreTokens()) { st = new StringTokenizer(br.readLine()); } return st.nextToken(); } }