ll qmi(ll a, ll k)
{
    ll res = 1;
    while(k)
    {
        if(k & 1) res = res * a % mod;
        a = a * a % mod;
        k >>= 1;
    }
    return res;
}

ll cal()
{
    ll res = 1;
    for(int i = 1; i <= n; i ++)
    {
        for(int j = i + 1; j <= n; j ++)
        {
            while(a[j][i])
            {
                ll t = a[i][i] * qmi(a[j][i], mod - 2) % mod;   
                for(int k = i; k <= n; k ++)
                    a[i][k] = (a[i][k] - t * a[j][k] + mod) % mod;
                swap(a[i], a[j]);
                res = -res;
            }
        }
        res = (res * a[i][i]) % mod;
    }
    return (res + mod) % mod;
}