#include <cstdio>
#include <iostream>
#include <algorithm>
using namespace std;
#define rep(i, l, r) for (int i = l; i <= r; ++i)
const int N = 1e6 + 5;
const int P = 998244353; 
int n, m, ans, fac[N], inv[N]; 

int inc (int a, int b) { return (a += b) >= P ? a - P : a; }
int dec (int a, int b) { return (a -= b) < 0 ? a + P : a; }
int mul (int a, int b) { return 1ll * a * b % P; }
int fpow (int a, int b) { int ans = 1; for ( ; b; a = mul(a, a), b >>= 1) if(b & 1) ans = mul(ans, a); return ans; }
int C (int n, int m) { return mul(fac[n], mul(inv[m], inv[n - m])); }
void init (int n) {
  fac[0] = inv[0] = 1;
  rep(i, 1, n) fac[i] = mul(fac[i - 1], i), inv[i] = fpow(fac[i], P - 2); 
}

int main () {
  ios :: sync_with_stdio(0), cin.tie(0), cout.tie(0); 
  cin >> n >> m, init(m); 
  /*rep(i, 1, n - 1) for (int j = 0; 2 * j < m; ++j)
    ans = inc(ans, mul(C(m, j), mul(fpow(i, j), fpow(n - i, m - j)))); */
  ans = mul(n - 1, fpow(n, m)); 
  if(m % 2 == 0) {
    rep(i, 1, n - 1) ans = dec(ans, mul(C(m, m / 2), mul(fpow(i, m / 2), fpow(n - i, m / 2)))); 
  }
  ans = mul(ans, fpow(2, P - 2)); 
  ans = inc(ans, fpow(n, m));
  cout << ans << '\n';  
  return 0; 
}