#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <numeric>
#include <ctime>
#include <bitset>
#include <complex>

using namespace std;

typedef long long ll;

const int MOD = 1e9 + 7;
const int MAXN = 253;

int add(int a, int b) {
    ll res = (ll)a + b;
    return res % MOD;
}

int sub(int a, int b) {
    ll res = (ll)a - b;
    res %= MOD;
    res += MOD;
    return res % MOD;
}

int mul(int a, int b) {
    ll res = (ll)a * b;
    return res % MOD;
}

int binpow(int a, int b) {
    int res = 1;
    while (b > 0) {
        if (b & 1) {
            res = mul(res, a);
        }
        a = mul(a, a);
        b /= 2;
    }
    return res;
}

int C[MAXN][MAXN + 1];

void init() {
    C[0][0] = 1;
    for (int i = 1; i < MAXN; i++) {
        C[i][0] = 1;
        for (int j = 1; j < i; j++) {
            C[i][j] = add(C[i - 1][j], C[i - 1][j - 1]);
        }
        C[i][i] = 1;
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    init();
    int n, cnt;
    cin >> n >> cnt;
    vector<int> cnt_binpows(n + 1);
    vector<int> cnt_mn_binpows(n + 1);
    for (int i = 0; i <= n; i++) {
        cnt_binpows[i] = binpow(cnt, i);
        cnt_mn_binpows[i] = binpow(cnt - 1, i);
    }
    int cnt_ok_columns = sub(binpow(cnt, n), binpow(cnt - 1, n));
    vector<vector<int>> dp(n + 1, vector<int> (n + 1));
    dp[0][n] = 1;
    for (int i = 0; i < n; i++) {
        for (int j = 1; j <= n; j++) {
            for (int k = 1; k <= j; k++) {
                int ml = mul(C[j][k], cnt_binpows[n - j]);
                ml = mul(ml, cnt_mn_binpows[j - k]);
                dp[i + 1][j - k] = add(dp[i + 1][j - k], mul(ml, dp[i][j]));
            }
            {
                int ml = sub(cnt_binpows[n - j], cnt_mn_binpows[n - j]);
                ml = mul(ml, cnt_mn_binpows[j]);
                dp[i + 1][j] = add(dp[i + 1][j], mul(ml, dp[i][j]));
            }
        }
        dp[i + 1][0] = add(dp[i + 1][0], mul(cnt_ok_columns, dp[i][0]));
    }
    cout << dp[n][0] << endl;
}