#include <stdio.h>
#include <string.h>

#include <algorithm>

#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

typedef long long LL;
constexpr int N = 1000005;
constexpr int mod = 998244353;

constexpr int inv(int x, int k = mod - 2) {
	int r = 1;
	while (k) {
		if (k & 1) {
			r = x * (LL)r % mod;
		}
		x = x * (LL)x % mod;
		k >>= 1;
	}
	return r;
}

int fact[N], infact[N];

void pref() {
	constexpr int n = 1000000;
	*fact = 1;
	for (int i = 1; i <= n; ++i) {
		fact[i] = fact[i - 1] * (LL)i % mod;
	}
	infact[n] = inv(fact[n]);
	for (int i = n; i; --i) {
		infact[i - 1] = infact[i] * (LL)i % mod;
	}
}

int C(int x, int y) {
	return y < 0 || x < y ? 0 : fact[x] * (LL)infact[y] % mod * infact[x - y] % mod;
}

int main() {
	pref();
	int n, m;
	scanf("%d%d", &n, &m);
	int res = (n / 2 + 1ll) * inv(n, m) % mod;
	if (!(m & 1)) {
		int s = 0;
		for (int x = 1; x <= (n - 1) / 2; ++x) {
			s = (s + inv(x, m / 2) * (LL)inv(n - x, m / 2)) % mod;
		}
		res = (res - s * (LL)C(m, m / 2)) % mod;
	}
	if (!(n & 1)) {
		int s = inv(2, m);
		if (!(m & 1)) {
			s = (s + C(m, m / 2)) % mod;
		}
		s = s * (LL)inv(2) % mod;
		res = (res - inv(n / 2, m) * (LL)s) % mod;
	}
	if (res < 0) {
		res += mod;
	}
	printf("%d\n", res);
	return 0;
}