#include <bits/stdc++.h>
using namespace std;
namespace Wilson_Inversion {
    void main();
}
int main() {
    return Wilson_Inversion::main(), 0;
}
namespace Wilson_Inversion {

typedef long long i64;
typedef unsigned long long ui64;
const i64 mod = 998244353;
i64 f[1000010];

i64 qp(i64 x, int y) {
    i64 res = 1;
    while (y) {
        if (y & 1) (res *= x) %= mod;
        (x *= x) %= mod;
        y >>= 1;
    }
    return res;
}

void solve() {
    int n, m;
    cin >> n >> m;
    i64 bs = 1;
    i64 sm = 0;
    for (int i = 1; i <= n; ++i) {
        (sm *= m) %= mod;
        if (!(i & 1)) (sm += f[i / 2]) %= mod;
        (bs *= m) %= mod;
        f[i] = (bs - sm + mod) % mod;
    }
    i64 ans = 0;
    for (int i = 1; i < (n + 1) / 2; ++i) {
        ans += f[i] * qp(m, n - i * 2);
        ans %= mod;
    }
    cout << ans << '\n';
}

void main() {
    ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    int T = 1;
    // cin >> T;
    while (T--) solve();
}

}