#include <iostream>
#include <algorithm>
#include <fstream>
#include <vector>
#include <map>
#include <queue>
using namespace std;

ifstream fin("fantasy.in");
ofstream fout("fantasy.out");

const int MAXN = 1010;

int t, n, d, c, v, last[MAXN], dist[MAXN], visited[MAXN], urm[MAXN], mark[MAXN], gtc[MAXN], gtcb[MAXN];
vector<int> graph[MAXN];

int get_dist(int start, int finish) {
  queue<int> coada;

  coada.push(start);
  dist[start] = 0;

  for (int i = 1; i <= n; ++i)
    visited[i] = 0;

  while (!coada.empty()) {
    int nod = coada.front();
    coada.pop();
    visited[nod] = 1;

    //cout << nod << endl;

    for (auto it : graph[nod]) {
        if (!visited[it]) {
          last[it] = nod;
          dist[it] = dist[nod] + 1;
          visited[it] = 1;
          if (it == finish)
            return dist[it];
          coada.push(it);
        }
    }
  }
  //cout << "CEVA PLM" << endl;
  return -1;
}

int main() {
  fin >> t;

  for (; t; --t) {
      fin >> n >> d >> c >> v;
      for (int i = 1; i <= n; ++i)
        mark[i] = 0;

      for (int i = 1; i <= n; ++i)
        graph[i].clear();

      for (int i = 1; i < n; ++i) {
        int x, y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
      }
      //cout << "MERGE" << endl;

      //cout << "MERGE" << endl;


      int dist2 = get_dist(c, v);
      int dist1 = get_dist(d, v);

      for (int i = 1; i <= n; ++i)
        gtc[i] = last[i];


      for (int nod = v; nod != d; nod = gtc[nod])  {
          gtcb[gtc[nod]] = nod;
      }

      get_dist(d, c);
      //cout << "MERG DISTANTELE" << endl;
      for (int nod = c; nod != d; nod = last[nod])  {
        urm[last[nod]] = nod;
        mark[nod] = 1;
      }

      mark[d] = 1;

      int moare = 0;

      cout << dist1 << " " << dist2 << " " << mark[v] << endl;
      //break;

      if (!mark[v]) {
        if (dist1 >= dist2) {
          fout << "DA\n";
          continue;
        }
        while (!mark[v] && !moare) {
          if (gtc[v] == d || gtc[v] == c) {
            moare = 1;
          }
          if (gtcb[d] != urm[d]) {
            moare = 1;
          }
          v = gtc[v];
          d = urm[d];
          c = last[c];
          if (v == c || v == d) {
            moare = 1;
          }
        }
        if (moare) {
          fout << "NU\n";
          continue;
        }
      }

      //cout << v << d << c << endl;

      int canEvasion = 0;
      int bestEvasion = 0;

      if (graph[v].size() > 2) {
        canEvasion = 1;
      }

      int curEvasion = 0;

      //cout << "NU AICI!\n" << endl;

      int cv = v, cd = d, cc = c;

      while (last[v] != urm[d] && last[v] != d) { // cat timp nu ne lovim de dragon scapam de el
        v = last[v];
        c = last[c];
        d = urm[d];
        --curEvasion;

        if (graph[v].size() > 2) {
          canEvasion = 1;
          bestEvasion = curEvasion;
          break;
        }
      }


      v = cv;
      d = cd;
      c = cc;

      curEvasion = 0;

      while (urm[v] != last[c] && urm[v] != c) { // cat timp nu ne lovim de cavaler scapam de el
        v = urm[v];
        c = last[c];
        d = urm[d];
        ++curEvasion;

        if (graph[v].size() > 2) {
          canEvasion = 1;
          bestEvasion = curEvasion;

        }
      }

      if (!canEvasion) {
        fout << "NU\n";
        continue;
      }
      if (dist1 >= dist2 - bestEvasion * 2) {
        fout << "DA\n";
      } else {
        fout << "NU\n";
      }
    }

    return 0;
}