#include <iostream>
#include <algorithm>
#include <utility>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <math.h>
#include <string.h>
#include <iomanip>
#include <numeric>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <functional>
#include <limits>
#include <cassert>
#include <bitset>
#include <chrono>
#include <random>
#include <memory>
 
/* macro */
 
#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, a, n) for (int i = ((int)(n-1)); i >= (int)(a); i--)
#define Rep(i, a, n) for (i64 i = (i64)(a); i< (i64)(n); i++)
#define RRep(i, a, n) for (i64 i = ((i64)(n-i64(1))); i>=(i64)(a); i--)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
 
/* macro end */
 
/* template */
 
namespace ebi {
 
#ifdef LOCAL
#define debug(...)                                                    \
    std::cerr << "LINE: " << __LINE__ << "  [" << #__VA_ARGS__ << "]:", \
        debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif
 
void debug_out() { std::cerr << std::endl; }
 
template <typename Head, typename... Tail>
void debug_out(Head h, Tail... t) {
    std::cerr << " " << h;
    if (sizeof...(t) > 0) std::cout << " :";
    debug_out(t...);
}
 
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, std::pair<T1, T2> pa) {
    return os << pa.first << " " << pa.second;
}
 
template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
    for (std::size_t i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : " ");
    return os;
}
 
using size_t = std::size_t;
using i64 = long long;
using u64 = unsigned long long;
 
template<class T> void fill(std::vector<T> &v) { for(T &e: v) std::cin >> e; }
 
template<class T>
struct Edge {
    int to;
    T cost;
    Edge(int to, T cost) : to(to), cost(cost) { }
};
 
template<class T>
using Graph = std::vector<std::vector<Edge<T>>>;
 
using graph = std::vector<std::vector<int>>;
 
template <class T>
inline bool chmin(T &a, T b) {
    if (a > b){
        a = b;
        return true;
    }
    return false;
}
 
template <class T>
inline bool chmax(T &a, T b) {
    if (a < b){
        a = b;
        return true;
    }
    return false;
}
 
template <class T>
T gcd(T a, T b){
    if( b==0 ) return a;
    else return gcd(b, a%b);
}
 
template <class T>
T lcm(T a, T b) {
    return (a*b)/gcd(a,b);
}
 
template<class T>
T Pow(T x, i64 n) {
    T res = 1;
    while(n>0){
        if(n&1) res = res *x;
        x = x*x;
        n>>=1;
    }
    return res;
}
 
template<class T>
T scan() {
    T val;
    std::cin >> val;
    return val;
}
 
constexpr i64 LNF = std::numeric_limits<i64>::max()/4;
 
constexpr int INF = std::numeric_limits<int>::max()/4;
 
const long double PI = acos(-1);
 
const std::vector<int> dy = {1,0,-1,0,1,1,-1,-1};
const std::vector<int> dx = {0,1,0,-1,1,-1,1,-1};
 
}
 
/* template end */

/*
    author: noshi91
    reference: https://noshi91.hatenablog.com/entry/2019/03/31/174006
    noshi91のブログで公開されているmodintを元にinv(), pow()を追加したものです
*/

#include <cstdint>
#include <iostream>

namespace ebi {

template<std::uint_fast64_t Modulus>
class modint {
  using u64 = std::uint_fast64_t;

public:
    u64 a;

    constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr u64 &val() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr modint operator+(const modint rhs) const noexcept {
        return modint(*this) += rhs;
    }
    constexpr modint operator-(const modint rhs) const noexcept {
        return modint(*this) -= rhs;
    }
    constexpr modint operator*(const modint rhs) const noexcept {
        return modint(*this) *= rhs;
    }
    constexpr modint operator/(const modint rhs) const noexcept {
        return modint(*this) /= rhs;
    }
    constexpr modint &operator+=(const modint rhs) noexcept {
        a += rhs.a;
        if (a >= Modulus) {
            a -= Modulus;
        }
        return *this;
    }
    constexpr modint &operator-=(const modint rhs) noexcept {
        if (a < rhs.a) {
        a += Modulus;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr modint &operator*=(const modint rhs) noexcept {
        a = a * rhs.a % Modulus;
        return *this;
    }
    constexpr modint &operator/=(modint rhs) noexcept {
        u64 exp = Modulus - 2;
        while (exp) {
        if (exp % 2) {
            *this *= rhs;
        }
        rhs *= rhs;
        exp /= 2;
        }
        return *this;
    }
    constexpr modint operator-() const { return modint() - *this; }
    bool operator==(const u64 rhs) {
        return a == rhs;
    }
    bool operator!=(const u64 rhs) {
        return a != rhs;
    }
    constexpr modint& operator++() {
        a++;
        if( a == mod() ) a = 0;
        return *this;
    }
    constexpr modint& operator--() {
        if( a == 0 ) a = mod();
        a--;
        return *this;
    }

    modint pow(u64 n) const noexcept {
        modint res = 1;
        modint x = a;
        while(n>0){
            if(n&1) res *= x;
            x *= x;
            n >>=1;
        }
        return res;
    }
    modint inv() const {
        return pow(Modulus-2);
    }

    static u64 mod() {
        return Modulus;
    }
};

using modint998244353 = modint<998244353>;
using modint1000000007 = modint<1000000007>;

template<std::uint_fast64_t Modulus>
std::ostream& operator<<(std::ostream& os, modint<Modulus> a){
    return os << a.val();
}

} // namespace ebi

namespace ebi {

using mint = modint998244353;

using ld = long double;

void main_() {
    const i64 n = scan<i64>(), m = scan<i64>();
    mint ans = 0;
    mint inv_two = mint(2).inv();
    rep(i,1,m) {
        mint ret = 0;
        if(i == 1) {
            ret = mint(2).pow(n) - 2;
        }
        else {
            ret = mint(i+1).pow(n)-mint(i-1).pow(n) - mint(2)*(mint(i).pow(n) - mint(i-1).pow(n));
        }
        mint tmp = mint(i+2)*mint(m-i) + mint(m-i)*mint(m-i-1);
        tmp *= inv_two;
        ans += mint(i)*ret*tmp*mint(n);
    }
    std::cout << ans << std::endl;
}
 
}

 
int main() {
    std::cout << std::fixed << std::setprecision(15);
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);
    ebi::main_();
    return 0;
}