#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;
}