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

const int N=1e6+5;
const ll M=998244353;

int n,m;
ll dp[N],sum[N];

ll qpow(ll x,ll k){
    ll ans=1;
    while(k){
        if(k&1) ans=ans*x%M;
        x=x*x%M;
        k>>=1;
    }
    return ans;
}

ll inv(ll n){return qpow(n,M-2);}

void solve(){
    cin>>n>>m;
    ll rev=qpow(m*m-1,M-2);
    for(int i=1;i<=n;i++){
        int k=i/2;
        dp[i]=qpow(m,i)*sum[k]%M;
        sum[i]=(sum[i-1]+(qpow(m,i)-dp[i]+M)%M*inv(qpow(m,2*i))%M)%M;
    }
    
    ll ans=0;
    for(int i=1;i*2<n;i++){
        ans=(ans+(qpow(m,i)-dp[i])%M*qpow(m,n-2*i))%M;
    }
    cout<<(ans+M)%M;
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n=1;
    //cin>>n;
    while(n--)solve();
    return 0;
}