#include<iostream>
#include<fstream>
#include<vector>
#include<stdio.h>
using namespace std;

#define NMAX 100001
#define MOD 1000000007
#define DIM 10000

vector <int> v[NMAX];
int viz[NMAX],k,sol,poz;
char buff[DIM+1];

void citeste(int &numar)
{
	while(buff[poz]<'0' || buff[poz]>'9') 
		if(++poz==DIM) {
			fread(buff,1,DIM,stdin);
			poz=0;
		}
	numar=0;
	while(buff[poz]>='0' && buff[poz]<='9') {
		numar=numar*10+buff[poz]-'0';
		if(++poz==DIM) {
			fread(buff,1,DIM,stdin);
			poz=0;
		}
	}
}

void dfs(int nod, int less)
{
	viz[nod]=1;
	for(vector <int> :: iterator it=v[nod].begin();it!=v[nod].end();it++)
		if(viz[*it]==0) {
			sol=(1LL*sol*(k-less))%MOD;
			less++;
			dfs(*it,1);
		}
	
}

int main ()
{
	int n,x,y,i;
	freopen("colorare3.in","r",stdin);
	ofstream g("colorare3.out");
	citeste(n);
	citeste(k);
	for(i=1;i<=n-1;i++) {
		citeste(x);
		citeste(y);
		v[x].push_back(y);
		v[y].push_back(x);
	}
	fclose(stdin);
	sol=1;
	dfs(1,0);
	g<<sol;
	g.close();
	return 0;
}