#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;
#define sc(a) scanf("%d", &a)
#define sc2(a, b) scanf("%d%d", &a, &b)
#define sc3(a, b, c) scanf("%d%d%d", &a, &b, &c)
#define pri(x) printf("%d\n", x)
#define prie(x) printf("%d ", x)
#define mp make_pair
#define pb push_back
#define BUFF ios::sync_with_stdio(false);
#define db(x) cerr << #x << " == " << x << endl
#define dbs(x) cerr << x << endl
#define imprime(x, Y)                              \
  for (int X = 0; X < Y; X++) cerr << x[X] << " "; \
  cerr << endl;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vector<ii> > vvii;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fll;
const ld pi = acos(-1);
const int MOD = 1e9 + 7;
const int N = 100010;
int t, c, k, n;
vi graph[N];
int us[N], level[N], level2[N];
void dfs(int u, int l)
{
  us[u] = 1, level[u] = l;
  for (int v : graph[u])
    if (!us[u]) dfs(v, l + 1);
}
void dfs2(int u, int l)
{
  us[u] = 1, level2[u] = l;
  for (int v : graph[u])
    if (!us[u]) dfs2(v, l + 1);
}
ii extremos()
{
  int b = -1, e = -1;
  memset(us, 0, sizeof(us));
  dfs(1, 1);
  int idx = 0, romario = 0;
  for (int i = 1; i <= n; i++)
    if (level[i] < romario) romario = level[i], idx = i;
  memset(us, 0, sizeof(us));
  b = idx;
  dfs(b, 1);
  idx = 0, romario = 0;
  memset(level, 0, sizeof(level));
  for (int i = 1; i <= n; i++)
    if (level[i] < romario) romario = level[i], idx = i;
  e = idx;
  return mp(b, e);
}
int main()
{
  sc(t);
  for (int Y = 0; Y < t; Y++) {
    for (int i = 0; i < N; i++) graph[i].clear();
    sc2(c, k);
    for (int j = 0; j < c; j++) {
      sc(n);
      for (int i = 2; i <= n; i++) {
        int x;
        sc(x);
        graph[x].pb(i);
        graph[i].pb(x);
      }
      ii ext = extremos();
      memset(us, 0, sizeof(us));
      dfs(ext.first, 0);
      memset(us, 0, sizeof(us));
      dfs2(ext.second, 0);
      for (int i = 1; i <= n; i++) level[i] = max(level[i], level2[i]);
      int menorigual = 0;
      for (int i = 1; i <= n; i++) menorigual += (level[i] <= k);
      double prob = menorigual / (double)n;
    }
  }
  return 0;
}