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] = (ndp[i-2]+dp[i]*i % 998244353*(i-1) %
                        998244353*inv2) % 998244353
        ndp[i] = (ndp[i]+dp[i]*i % 998244353*(N+1-i)) % 998244353
        if i+2 <= N+1:
            ndp[i+2] = (ndp[i+2]+dp[i]*(N+1-i) %
                        998244353*(N-i) % 998244353*inv2) % 998244353
    for i in range(N+2):
        dp[i] = ndp[i] % 998244353

print(dp[0])