N, M = map(int, input().split())
A = list(map(int, input().split()))
MOD = 998244353
cnt = 0
f = 0
for i in A:
    if i != f:
        cnt += 1
        f = i
cnt += f
dp = [0]*(N+2)
dp[cnt] = 1
inv2 = (MOD+1)//2
for _ in range(M):
    ndp = [0] * (N+2)
    for i in range(N+2):
        if i-2 >= 0:
            ndp[i-2] += (dp[i]*i*(i-1)*inv2) % MOD
        ndp[i] += (dp[i]*i*(N+1-i)) % MOD
        if i+2 <= N+1:
            ndp[i+2] += (dp[i]*(N+1-i)*(N-i)*inv2) % MOD
    for i in range(N+2):
        dp[i] = ndp[i] % MOD

print(dp[0])