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

using ll = long long;
#define int ll
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
using pii = pair<int, int>;
using vi = vector<int>;
#define fi first
#define se second
#define pb push_back

const int mod = 998244353;
int bpow(int a, int b)
{
    int r = 1;
    while (b > 0)
    {
        if (b%2)
            r = r*a%mod;
        a = a*a%mod;
        b/=2;
    }
    return r;
}

const int N = 1005000;
int dp[N];
int sumdp[N];

signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    int n, m;
    cin>>n>>m;
    for (int i=1; i<=n; i++)
    {
        int ans = bpow(m, i);
        ans = (ans - sumdp[i/2]*bpow(m, i))%mod;
//        for (int j=1; 2*j<=i; j++)
//            ans = (ans - dp[j]*bpow(m, i-2*j))%mod;
        dp[i] = (ans + mod)%mod;
        sumdp[i] = (sumdp[i-1] + dp[i]*bpow(m, mod-1-2*i))%mod;
    }

    int ans = 0;
    for (int i=1; i+i < n; i++)
        ans = (ans + dp[i]*bpow(m, n-2*i))%mod;
    cout<<ans<<"\n";
}