import sys
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
INF = 2 ** 63 - 1
mod = 998244353
class Combinatorics():
    def __init__(self, mod, maxi = 3 * 10 ** 6):
        self.mod = mod
        self.maxi = maxi
        self.facs = [1, 1]
        self.factinvs = [1, 1]
        self.invs = [0, 1]
        for i in range(2, self.maxi + 1):
            self.facs.append((self.facs[-1] * i) % self.mod)
            self.invs.append((-self.invs[self.mod % i] * (self.mod // i)) % self.mod)
            self.factinvs.append((self.factinvs[-1] * self.invs[-1]) % self.mod)
            
    def choose(self, n, k) -> int:
        if k < 0 or k > n: return 0
        if k == 0 or k == n: return 1
        k = min(k, n - k)
        return (((self.facs[n] * self.factinvs[k]) % self.mod) * self.factinvs[n-k]) % self.mod
    
    def perm(self, n, k) -> int:
        return (self.choose(n, k) * self.facs[k]) % self.mod

    def homop(self, n, k) -> int:
        if n == k == 0:
            return 1
        return self.choose(n + k - 1, k)

    def factorial(self, n):
        return self.facs[n]


n = ii()
s = input()
C = Combinatorics(mod, maxi = 10 ** 6)
a = s.count('A')
b = s.count('B')
c = s.count('C')
d = s.count('D')

A = a + b
B = c + d

ans = C.choose(A + B, A)

print(ans)