program colorare3;
const c=1000000007;
type vector=array[1..100000] of longint;
var a:vector;
    i,o:text;
    f,g,x,y,n,k,rez:longint;
function factorial(x:longint):longint;
var f:longint;
begin
  factorial:=1;
  for f:=2 to x do
    factorial:=((factorial mod c)*(f mod c))mod c
end;
begin
  rez:=1;
  assign(i,'colorare3.in');
  reset(i);
  readln(i,n,k);
  for f:=1 to n do
    a[f]:=0;
  for f:=1 to n-1 do
      begin
        readln(i,x,y);
        a[x]:=a[x]+1;
        a[y]:=a[y]+1
      end;
  for f:=1 to n do
    begin
      rez:=(((factorial(k-1)*(a[f]-1)) mod c) * rez)mod c
    end;
  assign(o,'colorare3.out');
  rewrite(o);
  write(o,rez);
  close(o)
end.