N, K = map(int, input().split())
A = list(map(int, input().split()))

MOD = 998244353

def inverse(n, d):
    return n * pow(d, -1, MOD) % MOD

l, r = 1, 1
for a in A:
    if a <= K-1:
        pass
    else:
        l *= inverse(K-1, a)
        l %= MOD
    if a <= K:
        pass
    else:
        r *= inverse(K, a)
        r %= MOD

print((r-l)%MOD)