import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
mod  = 998244353
n = ni()
s = input()
a = 0
c = 0
for i in range(n):
    if s[i] == "A" or s[i]=="B":
        a += 1
    else:
        c += 1
ans = 1
for i in range(n):
    ans *= i+1
    ans %= mod
for i in range(a):
    ans *= pow(i+1,mod-2,mod)
    ans %= mod
for i in range(c):
    ans *= pow(i+1,mod-2,mod)
    ans %= mod
print(ans)