#include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 10;
const int mod = 998244353;
int n, m;
int pw[N];
int ipw[2 * N];
int f[N];
int s[N];

int add(int x, int y) {
    return x + y >= mod ? x + y - mod : x + y;
}

int qpow(int a, int b = mod - 2) {
    int res = 1;
    while (b) {
        if (b & 1) res = 1ll * res * a % mod;
        a = 1ll * a * a % mod;
        b >>= 1;
    }
    return res;
}

int main() {
    scanf("%d%d", &n, &m);
    // for (int )
    pw[0] = 1;
    for (int i = 1; i <= n; ++i) {
        pw[i] = 1ll * pw[i - 1] * m % mod;
    }
    ipw[0] = 1;
    ipw[1] = qpow(m);
    for (int i = 2; i <= 2 * n; ++i) {
        ipw[i] = 1ll * ipw[i - 1] * ipw[1] % mod;
    }
    f[1] = m;
    f[0] = 1;
    s[1] = 1ll * f[1] * ipw[2] % mod;
    for (int i = 2; i <= n; ++i) {
        f[i] = 1ll * pw[i] * add(1, mod - s[i / 2]) % mod;
        s[i] = add(s[i - 1], 1ll * f[i] * ipw[2 * i] % mod);
    }
    int ans = pw[n];
    ans = add(ans, mod - f[n]);
    if (~n & 1) ans = add(ans, mod - f[n / 2]);
    printf("%d\n", ans);
    return 0;
}