MOD = 998244353
fac = [1] * (3 * 10 ** 5 + 1)
for i in range(len(fac) - 1):
    fac[i + 1] = fac[i] * (i + 1) % MOD

def comb(n, k):
    return fac[n] * pow(fac[n - k] * fac[k], MOD - 2, MOD) % MOD

n = int(input())
s = input()
print(comb(n, s.count('C') + s.count('D')))