#include <bits/stdc++.h>
#ifdef CKISEKI
#define safe cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n"
#define debug(a...) debug_(#a, a)
#define orange(a...) orange_(#a, a)
using std::cerr;
template <typename ...T>
void debug_(const char *s, T ...a) {
    cerr << "\e[1;32m(" << s << ") = (";
    int cnt = sizeof...(T);
    (..., (cerr << a << (--cnt ? ", " : ")\e[0m\n")));
}
template <typename Iter>
void orange_(const char *s, Iter L, Iter R) {
    cerr << "\e[1;32m[ " << s << " ] = [ ";
    for (int f = 0; L != R; ++L)
        cerr << (f++ ? ", " : "") << *L;
    cerr << " ]\e[0m\n";
}
#else
#define safe ((void)0)
#define debug(...) safe
#define orange(...) safe
#endif
#define all(v) begin(v), end(v)

using namespace std;


const int mod = 998244353;
void imadd(int &x, int y) {
    x = (x + y >= mod ? x + y - mod : x + y);
}
int mul(int64_t a, int64_t b) {
    return static_cast<int>(a * b % mod);
}

const int maxn = 3025;

int dp[maxn][maxn];
int fac[maxn], ifac[maxn], inv[maxn];
int comb(int a, int b) {
    return mul(fac[a], mul(ifac[b], ifac[a - b]));
}

int main() {
    inv[1] = 1;
    for (int i = 2; i < maxn; i++)
        inv[i] = mul(inv[mod % i], mod - mod / i);
    fac[0] = ifac[0] = 1;
    for (int i = 1; i < maxn; i++)
        fac[i] = mul(fac[i - 1], i), ifac[i] = mul(ifac[i - 1], inv[i]);
    cin.tie(nullptr)->sync_with_stdio(false);
    int N, M;
    cin >> N >> M;

    dp[0][0] = 1;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j <= i; j++) {
            imadd(dp[i + 1][j + 1], dp[i][j]);
            imadd(dp[i + 1][j], mul((1LL * j * (M - 2) - (i - j)) % mod, dp[i][j]));
        }
    }

    int ans = 0;
    for (int i = 0; i <= N; i++) {
        for (int j = 0; j <= N; j++) {
            imadd(ans, mul(dp[i][j], comb(N, i)));
        }
    }
    cout << ans << '\n';
}