#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define debug(x) cerr << #x << ": " << x << '\n'
#define debug2(x, y) debug(x), debug(y)
#define repn(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(i, a) for(int i = 0; i < (int)(a); i++)
#define all(v) v.begin(), v.end()
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define sq(x) ((x) * (x))
#define sz(x) (int)(x.size())
#define make_unique(x) sort(all((x))); (x).resize(unique(all((x))) - (x).begin())
const int MOD = 998244353;

mt19937 rng((ll)std::chrono::steady_clock::now().time_since_epoch().count());

ll n, m;

ll mypow(ll a, ll p){
	if(!p) return 1LL;
	if(p & 1) return (a * mypow(a, p - 1)) % MOD;
	ll x = mypow(a, p / 2);
	return (x * x) % MOD;
}

void solve(){
	cin >> n >> m;
	vector<ll> D(n + 1, 0LL), D1(n + 1, 0LL);
	repn(i, 2, n + 1){
		if(i >= 3){
			D[i] = (D[i - 1] * m) % MOD;
			if(i & 1){
				int h = i / 2;
				(D[i] += mypow(m, h + 1) + (MOD - ((D1[h] * m) % MOD))) %= MOD;
			}
		}
		D1[i] = (D1[i - 1] * m) % MOD;
		if(i % 2 == 0){
			int h = i / 2;
			(D1[i] += mypow(m, h) + (MOD - D1[h])) %= MOD;
		}
	}
	cout << D[n] << '\n';
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	//freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
	int t = 1;
	//cin >> t;
	while(t--) solve();
	return 0;
}