#include <bits/stdc++.h>

using i64 = long long;

constexpr int N = 1e6 + 5, P = 998244353;

template<typename T>
T power(T a, i64 b) {
	T ret = 1;
	while (b) {
		if (b & 1) ret = ret * a;
		a = a * a;
		b >>= 1;
	}
	return ret;
}

template<int P>
struct ModInt {
	int val;

	static inline int norm(int x) {
		if (x < 0)  x += P;
		if (x >= P) x -= P;
		return x; 
	}

	ModInt operator - () const { return ModInt(P - val); }
	inline ModInt inv() const { return power(*this, P - 2); }

	ModInt() {}
	ModInt(int val) : val(norm(val % P)) {}
	ModInt(i64 val) : val(norm(val % P)) {}

	bool constexpr operator <  (const ModInt &rhs) const { return val < rhs.val; }
	bool constexpr operator == (const ModInt &rhs) const { return val == rhs.val; }
	bool constexpr operator != (const ModInt &rhs) const { return val != rhs.val; }

	ModInt &operator += (const ModInt &rhs) & { return val = norm(val + rhs.val), *this; }
	ModInt &operator -= (const ModInt &rhs) & { return val = norm(val - rhs.val), *this; }
	ModInt &operator *= (const ModInt &rhs) & { return val = 1ll * val * rhs.val % P, *this; }
	ModInt &operator /= (const ModInt &rhs) & { return *this *= rhs.inv(); }

	ModInt constexpr operator + (const ModInt &rhs) const { ModInt ret = *this; return ret += rhs; }
	ModInt constexpr operator - (const ModInt &rhs) const { ModInt ret = *this; return ret -= rhs; }
	ModInt constexpr operator * (const ModInt &rhs) const { ModInt ret = *this; return ret *= rhs; }
	ModInt constexpr operator / (const ModInt &rhs) const { ModInt ret = *this; return ret /= rhs; }

	friend std::istream& operator >> (std::istream& is, ModInt &rhs) {
        i64 val; is >> val;
        return rhs.val = norm(val % P), is;
    }
    friend constexpr std::ostream& operator << (std::ostream& os, const ModInt &rhs) { 
    	return os << rhs.val; 
    }
};

using Z = ModInt<P>;

int n, m;

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);

	std::cin >> n >> m;
	Z ans = 0;
	for (int x = 1; x <= m; x++) ans += power(Z(m), n) - power(Z(x), n);
	std::cout << ans * 2 + power(Z(m), n) << "\n";

	return 0;
}