#include <bits/stdc++.h>
using namespace std;
const int64_t mod = 998'244'353;
int64_t mpow(int64_t b, int64_t e) {
  int64_t r = 1;
  while (e) {
    if (e & 1) {
      r *= b;
      r %= mod;
    }
    b *= b;
    b %= mod;
    e >>= 1;
  }
  return r;
}
inline int64_t minv(int64_t b) {
  return mpow(b, mod - 2);
}
int main() {
  ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
  int64_t n;
  int m;
  cin >> n >> m;
  int64_t f = 0;
  for (int i = 0; i < m; ++i) {
    int64_t sum_max_upper = (n % mod) * (i + 2);
    sum_max_upper %= mod;
    sum_max_upper *= minv(2);
    sum_max_upper %= mod;
    sum_max_upper *= mpow(i + 1, n);
    sum_max_upper %= mod;

    int64_t sum_max_lower = (n % mod) * (i + 1);
    sum_max_lower %= mod;
    sum_max_lower *= minv(2);
    sum_max_lower %= mod;
    sum_max_lower *= mpow(i, n);
    sum_max_lower %= mod;

    int64_t sum_min_upper = (n % mod) * (m + i + 2);
    sum_min_upper %= mod;
    sum_min_upper *= minv(2);
    sum_min_upper %= mod;
    sum_min_upper *= mpow(m - i - 1, n);
    sum_min_upper %= mod;

    int64_t sum_min_lower = (n % mod) * (m + i + 1);
    sum_min_lower %= mod;
    sum_min_lower *= minv(2);
    sum_min_lower %= mod;
    sum_min_lower *= mpow(m - i, n);
    sum_min_lower %= mod;

    int64_t sum_max = sum_max_upper - sum_max_lower;
    sum_max %= mod;

    int64_t sum_min = sum_min_lower - sum_min_upper;
    sum_min %= mod;

    f += sum_max * (i + 1);
    f %= mod;
    f -= sum_min * (i + 1);
    f %= mod;
  }
  f = (f + mod) % mod;
  cout << f << "\n";

  return 0;
}