MOD = 998244353

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

def geometric_progression(a, r, n):
    # a = 初項 r = 公比 n = 項数
    return a*((pow(r, n, MOD)-1)%MOD)%MOD*inverse(1, r-1)%MOD

N, M = map(int, input().split())

if N == 1:
    exit(print(0))
if M == 1:
    exit(print(N%2^1))

N -= 1
ans = 0
if N%2 == 1:
    l, r = 1, N
    ans += geometric_progression(M%MOD, M*M%MOD, (r-l)//2+1)
    ans %= MOD
    l, r = 2, N-1
    ans -= geometric_progression(M*M%MOD, M*M%MOD, (r-l)//2+1)
    ans %= MOD
else:
    l, r = 2, N
    ans += geometric_progression(M*M%MOD, M*M%MOD, (r-l)//2+1)
    ans %= MOD
    l, r = 1, N-1
    ans -= geometric_progression(M%MOD, M*M%MOD, (r-l)//2+1)
    ans %= MOD

print(ans)