using System;
using System.Linq;
using System.Collections.Generic;

namespace Contest
{
    class Program
    {
        static void Main(string[] args)
        {
            ABC133.E();
        }

        class ABC133
        {
            public static void A()
            {
                var N = Read.Int();
                var A = Read.Int();
                var B = Read.Int();
                Console.WriteLine(Math.Min(N * A, B));
            }
            public static void B()
            {
                var N = Read.Int();
                var D = Read.Int();
                var X = Enumerable.Range(0, N).Select(i => Read.IntN()).ToArray();

                Func<int[], int[], bool> isZ = (a, b) =>
                {
                    var dist2 = a.Select((x, i) => (x - b[i]) * (x - b[i])).Sum();
                    for(int i = 0; i < 200; ++i)
                    {
                        if (i * i == dist2) { return true; }
                    }
                    return false;
                };

                int count = 0;
                for(int i = 0; i < N; ++i)
                {
                    for(int j = i + 1; j < N; ++j)
                    {
                        count += isZ(X[i], X[j]) ? 1 : 0;
                    }
                }
                Console.WriteLine(count);
            }
            public static void C()
            {
                var L = Read.Int() % 2019;
                var R = Read.Int() % 2019;
                if (L >= R) { R += 2019; }
                int min = 1000000000;
                for(int i = L; i < R; ++i)
                {
                    for(int j = i + 1; j <= R; ++j)
                    {
                        min = Math.Min(min, (i * j) % 2019);
                    }
                }
                Console.WriteLine(min);
            }
            public static void D()
            {
                var N = Read.Int();
                var A = Read.LongN();
                var X = new long[N];
                X[N - 1] = A.Sum() - Enumerable.Range(0, N / 2).Select(i => A[i * 2] * 2).Sum();
                for(int i = N - 2; i >= 0; --i)
                {
                    X[i] = A[i] * 2 - X[i + 1];
                }
                Console.WriteLine(String.Join(" ", X));
            }
            public static void E()
            {
                var N = Read.Int();
                var K = Read.Int();
                var Adj = Read.AdjacencyList(N, N - 1);
                MOD ans = K;
                HashSet<int> done = new HashSet<int>();
                done.Add(1);
                Queue<int> queue = new Queue<int>();
                queue.Enqueue(1);
                while (queue.Count > 0)
                {
                    var v = queue.Dequeue();
                    int child = 0;
                    foreach(var w in Adj[v])
                    {
                        if (!done.Contains(w))
                        {
                            child++;
                            done.Add(w);
                            queue.Enqueue(w);
                        }
                    }
                    for(int i = 0; i < child; ++i)
                    {
                        ans *= (K - (v == 1 ? 1 : 2) - i);
                    }
                }
                Console.WriteLine(ans.ToString());
            }
        }




        class Util
        {

        }
        struct MOD
        {
            public static long P = 1000000007;
            public readonly long V;

            public MOD(long a) { this.V = a; }
            public static implicit operator MOD(long a) { return new MOD(a); }
            public static MOD operator +(MOD a, MOD b) { return new MOD((a.V + b.V) % P); }
            public static MOD operator -(MOD a, MOD b) { return new MOD((a.V - b.V + P) % P); }
            public static MOD operator *(MOD a, MOD b) { return new MOD((a.V * b.V) % P); }
            public static MOD operator /(MOD a, MOD b) { return new MOD((a.V * b.Inverse().V) % P); }
            //public MOD Inverse() { return Util.Inverse(V, P); }
            public MOD Inverse()
            {
                long a = V, p = P;
                long b = p, c = 1, d = 0, e = 0, f = 0;
                while (b != 0)
                {
                    e = a / b;
                    f = b; b = a - e * b; a = f;
                    f = d; d = c - e * d; c = f;
                }
                c %= p;
                return c + (c < 0 ? p : 0);
            }
            //public MOD Power(long n) { return Util.Power(V, n, P); }
            public MOD Power(long n)
            {
                long a = V, p = P;
                long res = 1;
                long mult = a;
                for (int i = 0; i < 40; ++i)
                {
                    if ((n & ((long)1 << i)) > 0)
                    {
                        res = (res * mult) % p;
                    }
                    mult = (mult * mult) % p;
                }
                return res;
            }

            public override string ToString() { return V.ToString(); }
        }

        static class Read
        {
            static Queue<string> queue = new Queue<string>();
            static void Enqueue() { var ss = Console.ReadLine().Split(' '); foreach (var s in ss) { queue.Enqueue(s); } }
            public static int Int() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt32(queue.Dequeue()); }
            public static long Long() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt64(queue.Dequeue()); }
            public static string Str() { if (queue.Count == 0) { Enqueue(); } return queue.Dequeue(); }
            public static int[] IntN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray(); }
            public static long[] LongN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray(); }
            public static string[] StrN() { return Console.ReadLine().Split(' '); }
            public static Tuple<int, int>[] TupleInt(int n) { List<Tuple<int, int>> list = new List<Tuple<int, int>>(); for (int i = 0; i < n; ++i) { var ab = Read.IntN(); list.Add(new Tuple<int, int>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<long, long>[] TupleLong(int n) { List<Tuple<long, long>> list = new List<Tuple<long, long>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<long, long>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<string, string>[] TupleStr(int n) { List<Tuple<string, string>> list = new List<Tuple<string, string>>(); for (int i = 0; i < n; ++i) { var ab = Read.StrN(); list.Add(new Tuple<string, string>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<double, double>[] TupleDouble(int n) { List<Tuple<double, double>> list = new List<Tuple<double, double>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<double, double>(ab[0], ab[1])); } return list.ToArray(); }
            public static long[,] LongMatrix(int r, int c)
            {
                var mat = new long[r, c];
                for (int i = 0; i < r; ++i)
                {
                    var x = Read.LongN();
                    for (int j = 0; j < c; ++j)
                    {
                        mat[i, j] = x[j];
                    }
                }
                return mat;
            }
            public static Dictionary<int, HashSet<int>> AdjacencyList(int N, int M, bool isDirectional = false)
            {
                Dictionary<int, HashSet<int>> dict = new Dictionary<int, HashSet<int>>();
                for (int i = 0; i <= N; ++i) { dict.Add(i, new HashSet<int>()); }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN(); dict[ab[0]].Add(ab[1]);
                    if (!isDirectional) { dict[ab[1]].Add(ab[0]); }
                }
                return dict;
            }
            public static Dictionary<int, Dictionary<int, long>> AdjacencyListWithWeight(int N, int M)
            {
                Dictionary<int, Dictionary<int, long>> dict = new Dictionary<int, Dictionary<int, long>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new Dictionary<int, long>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1], ab[2]);
                    dict[ab[1]].Add(ab[0], ab[2]);
                }
                return dict;
            }
        }
    }
}


Measured memory_bytes: 48988