#include <cstdio>

using namespace std;

const int N = 1e6 + 500;
const int MOD = 998244353;

inline int add(int A, int B ) {
	if(A + B >= MOD) return A + B - MOD;
	return A + B;
}

inline int sub(int A, int B ) {
	if(A - B < 0) return A - B + MOD;
	return A - B;
}

inline int mul(int A, int  B) {
	return (long long)A * B % MOD;
}

int potm[N], n, m, clean[N];

int main() {
	scanf("%d%d", &n, &m);
	potm[0] = 1;
	for(int i = 1;i < N;i++) potm[i] = mul(potm[i - 1], m);
	clean[1] = m;
	clean[2] = mul(m, m - 1);
	int suma = m;
	for(int i = 3;i <= n;i++) {
		suma = mul(suma, m);
		if(i % 2 == 0) suma = add(suma, clean[i / 2]);
		clean[i] = sub(potm[i], suma);
	}	
	int ans = 0;
	for(int i = 1;2 * i < n;i++) {
		ans = add(ans, mul(potm[n - 2 * i], clean[i]));
	}
	printf("%d\n", ans);
}