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

const int MOD = 998244353;

int add(int a, int b) {
    return a + b >= MOD ? a + b - MOD : a + b;
}

int sub(int a, int b) {
    return a >= b ? a - b : a + MOD - b;
}

int mul(int a, int b) {
    return (1ll * a * b) % MOD;
}

int pw(int x, int n) {
    int res = 1;
    while (n) {
        if (n % 2 == 0) {
            x = mul(x, x);
            n /= 2;
        } else {
            res = mul(res, x);
            --n;
        }
    }
    return res;
}

void solve_() {
    int n, m;
    cin >> n >> m;
    vector<int> pwm(n + 1);
    pwm[0] = 1;
    for (int i = 1; i <= n; ++i) {
        pwm[i] = mul(pwm[i - 1], m);
    }
    vector<int> cnt((n + 1) / 2);
    int sum = 0;
    int ans = 0;
    for (int l = 1; l * 2 < n; ++l) {
        sum = mul(sum, m);
        if (l % 2 == 0) {
            sum = add(sum, cnt[l / 2]);
        }
        cnt[l] = sub(pwm[l], sum);
        ans = add(ans, mul(cnt[l], pwm[n - 2 * l]));
    }
    cout << ans << "\n";
}

/// #define MULTITEST

main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int tst = 1;
#ifdef MULTITEST
    cin >> tst;
#endif // MULTITEST
    while (tst--) {
        solve_();
    }
    return 0;
}