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

const int N=1e6+10;
const int MOD=998244353;

typedef long long ll;

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

ll qpow(ll x,ll y=MOD-2){
    ll cnt=1;
    while(y){
        if(y&1) cnt=cnt*x%MOD;
        x=x*x%MOD;y>>=1;
    }
    return cnt;
}

int read(){
    int sym=1,num=0;char cnt=getchar();
    while(cnt<'0'||cnt>'9'){
        if(cnt=='-') sym=-1;
        cnt=getchar();
    }    
    while(cnt>='0'&&cnt<='9'){
        num=(num<<3)+(num<<1)+(cnt^48);
        cnt=getchar(); 
    }
    return sym*num;
}

int main(){
    n=read(),m=read();
    for(int i=1;i<=n;i++)
        dp[i]=g[i>>1]*qpow(m,i)%MOD,g[i]=(g[i-1]+qpow(qpow(m,i))-qpow(qpow(m,2*i))*dp[i])%MOD;
//    for(int i=1;i<=6;i++)
//        printf("%lld %lld\n",(g[i]%MOD+MOD)%MOD,(dp[i]%MOD+MOD)%MOD);
    if(n%2) printf("%lld\n",(dp[n]%MOD+MOD)%MOD);
    else printf("%lld\n",((dp[n]-(qpow(m,n>>1)-dp[n>>1]))%MOD+MOD)%MOD);
    return 0;
}