import sys
from collections import Counter

input = sys.stdin.readline
n = int(input().rstrip())
s = list(input().rstrip())
mod = 998244353

CC = Counter(s)

N = n + 5
bikkuri = [0] * N
bikkuri[0] = 1
gyaku = [0] * N
for i in range(1, N):
    bikkuri[i] = (i * bikkuri[i - 1]) % mod
gyaku[N - 1] = pow(bikkuri[N - 1], mod - 2, mod)
for i in range(N)[::-1]:
    gyaku[i - 1] = (gyaku[i] * i) % mod


def comb(n, r):
    if r < 0 or n - r < 0:
        return 0
    return bikkuri[n] * gyaku[r] % mod * gyaku[n - r] % mod


ans = 1

# ans *= comb(CC["A"] + CC["B"], CC["A"])
# ans *= comb(CC["C"] + CC["D"], CC["D"])
# ans %= mod
ans *= comb(CC["A"] + CC["B"] + CC["C"] + CC["D"], CC["A"] + CC["B"])
ans %= mod

print(ans)