#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

int main()
{
    ifstream in("itree.in");
    ofstream out("itree.out");
    int t;
    in >> t;
    while(t--)
    {
        int n, x, y;
        in >> n;
        vector<int> vecin(n+1);
        vector<int> grad(n+1);
        for(int i = 1; i < n; ++i)
        {
            in >> x >> y;
            vecin[x] = y;
            vecin[y] = x;
            grad[x]++, grad[y]++;
        }
        int gradMax = 0;
        for(int i = 1; i <= n; ++i)
        {
            if(grad[i] == 1)
            {
                grad[vecin[i]]--;
                grad[i] = 0;
            }
        }
        for(int i = 1; i <= n; ++i)
            gradMax = max(gradMax, grad[i]);
        if(gradMax > 2)
            out << "NO\n";
        else
            out << "YES\n";
    }
    in.close();
    out.close();
    return 0;
}