#include <bits/stdc++.h>
using namespace std;

const long long MOD = 998244353;

long long binpow(long long a, long long b) {
    if (b == 0) {
        return 1;
    }
    long long c = binpow(a, b / 2);
    if (b % 2 == 0) {
        return c * c % MOD;
    } else {
        return c * c % MOD * a % MOD;
    }
}

long long modinv(long long a) {
    return binpow(a, MOD - 2);
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int N, M;
    cin >> N >> M;
    vector<long long> powM(2 * N + 1);
    powM[0] = 1;
    for (int i = 1; i <= 2 * N; i++) {
        powM[i] = powM[i - 1] * M % MOD;
    }

    vector<long long> dp(N + 1);
    vector<long long> sum(N + 1);
    dp[1] = M;
    sum[1] = dp[1] * modinv(powM[2]) % MOD;
    for (int i = 2; i <= N; i++) {
        dp[i] = powM[i] - powM[i] * sum[i / 2] % MOD + MOD;
        dp[i] %= MOD;
        sum[i] = sum[i - 1] + dp[i] * modinv(powM[2 * i]) % MOD;
        sum[i] %= MOD;
    }
    long long res = powM[N] - dp[N];
    if (N % 2 == 0) {
        res -= dp[N / 2];
    }
    res = (res % MOD + MOD) % MOD;
    cout << res << "\n";
}