#include <iostream>
#include <vector>
#include "atcoder/modint.hpp"
#include "atcoder/convolution.hpp"
using namespace std;

const int mod = 998244353;
using mint = atcoder::modint998244353;

const int MX = 1010101;
mint fact[MX], finv[MX], inv[MX];

mint com(int n, int k) {
    if(n < 0 or k < 0 or n < k) return 0;
    return fact[n] * finv[k] * finv[n-k];
}

void init() {
    fact[0] = fact[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MX; i++) {
        fact[i] = fact[i-1] * i;
        inv[i] = mod - inv[mod%i] * (mod/i);
        finv[i] = finv[i-1] * inv[i];
    }
}

int main() {
    int n; long long k; cin >> n >> k;
    if (k == 1){
        cout << (n == 1 ? 1 : 0) << "\n";
        return 0;
    }
    init();
    vector<mint> kp(n+1), np(n+1), f(n+1);
    mint tk = 1, tn = 1;
    mint ni = mint(n).inv();
    mint coef = 1;
    for (int i = 0; i <= n; i++) {
        kp[i] = tk;
        tk *= k-1;
        np[i] = tn;
        tn *= ni;
        f[i] = coef * (i%2 ? -1:1);
        coef *= inv[i+1];
        coef *= k-1+i;
    }
    auto g = atcoder::convolution<mint>(kp,f);

    // tree
    mint ans = 0;
    for (int s = 0; s < n; s++) ans += g[s] * s * kp[n-s-1] * finv[n-s-1] * np[s];

    // cycle
    vector<mint> a(n+1);
    for (int i = 0; i <= n; i++) a[i] = kp[i] + (k-1) * (i%2 ? -1:1);
    auto h = atcoder::convolution(a,g);
    for (int s = 1; s <= n; s++) ans += h[s-1] * s * kp[n-s] * finv[n-s] * np[s];

    ans *= fact[n] * mint(n).pow(n-1);
    cout << ans.val() << "\n";
}