#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const int N = 100010;

int t, n, k;
int h[N], e[N], ne[N], idx;

void add(int a, int b)
{
    e[idx] = b, ne[idx] = h[a], h[a] = idx ++ ;
}

int dfs(int u)
{
    int sum = 1;
    for (int i = h[u]; i != -1; i = ne[i])
    {
        int j = e[i];
        int s = dfs(j);
        if (s == -1)  return -1;
        sum += s;
    }
    if (sum == k)  return 0;
    if (sum > k) return -1;
    return sum;
}

int main()
{
    cin >> t;

    while (t -- )
    {
        cin >> n >> k;
        memset(h, -1, sizeof h);
        for (int i = 0; i < n - 1; i ++ )
        {
            int a, b;
            cin >> a >> b;
            add(a, b);
        }

        if (n % k != 0)
        {
            cout << "NO" << endl;
            continue;
        }

        if (dfs(1) == 0)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}