//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx2") // doesn't work on Yandex
//#pragma GCC target("avx") // for old judges
//#pragma GCC target("bmi,bmi2,lzcnt,popcnt") // fast bit operations

#include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <queue>
#include <deque>
#include <cmath>
#include <algorithm>
#include <cassert>
#include <chrono>
#include <random>
#include <string>
#include <numeric>
#include <complex>
#include <tuple>
#include <utility>
#include <bitset>
#include <array>
#include <stack>
#include <sstream>
#include <unordered_set>

using namespace std;
typedef long long ll;

string to_string(string a) { return '"' + a + '"'; }
string to_string(char a) { return "'" + string(1, a) + "'"; }
string to_string(const char* a) { return to_string((string) a); }
string to_string(bool a) { return a ? "true" : "false"; }
template <class T1, class T2>
string to_string(pair<T1, T2> a) {
    return "(" + to_string(a.first) + ", " + to_string(a.second) + ")";
}
template <class T>
string to_string(T a) {
    bool first = true; string res = "{";
    for (const auto& i : a) {
        if (!first) res += ", ";
        first = false;
        res += to_string(i);
    }
    res += "}";
    return res;
}
void debug_out() { cerr << endl; }
template <class T1, class... T2>
void debug_out(T1 a, T2... b) {
    cerr << " " << to_string(a);
    debug_out(b...);
}

#ifdef LOCAL
#define out(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define out(...) 42
#endif

clock_t start_time; void start_timer() { start_time = clock(); }
double get_time() { return (double) (clock() - start_time) / CLOCKS_PER_SEC; }

void Solve();

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef LOCAL
    freopen("usr/share/man/man1/input.txt", "r", stdin);
#endif
    start_timer();
    Solve();
#ifdef LOCAL
    cerr << fixed << setprecision(3);
    cerr << endl << "Time spent: " << get_time() << endl;
#endif
    return 0;
}

// do something, stay focused
// look for stupid bugs
// guess, slow, stress
// don't overgeneralize
// don't rush

// don't waste time on standings

// SOLVE THE PROBLEM OR DIE TRYING
// THE SOLUTION IS ALWAYS SIMPLE
// THE CODE IS ALWAYS SHORT

const int N = 2e5 + 5;
const int inf = 1e9;

vector<int> g[N];
int d[3][N];
bool used[N];

int sum(int v) {
    return d[0][v] + d[1][v] + d[2][v];
}

void init(int n) {
    for (int i = 1; i <= n; i++) {
        g[i].clear();
        for (int j = 0; j <= 2; j++) {
            d[j][i] = inf;
        }
        used[i] = 0;
    }
}

void bfs(int id, int s, int n) {
    for (int i = 1; i <= n; i++) {
        used[i] = 0;
    }
    d[id][s] = 0;
    queue<int> q;
    q.push(s);
    d[id][s] = 0;
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        if (used[v]) continue;
        used[v] = 1;
        for (int u : g[v]) {
            if (used[u]) continue;
            if (d[id][u] > d[id][v] + 1) {
                d[id][u] = d[id][v] + 1;
                q.push(u);
            }
        }
    }
}

void Solve() {
    int T;
    cin >> T;
    while (T--) {
        int n;
        cin >> n;
        init(n);
        int a, b, c;
        cin >> a >> b >> c;
        for (int i = 1; i < n; i++) {
            int u, v;
            cin >> u >> v;
            g[u].push_back(v);
            g[v].push_back(u);
        }
        bfs(0, a, n);
        bfs(1, b, n);
        bfs(2, c, n);
        int cen = 1;
        for (int i = 1; i <= n; i++) {
            if (sum(i) < sum(cen)) {
                cen = i;
            }
        }
        string ans;
        if (cen == a) {
            ans = "A";
        }
        else if (cen == b) {
            ans = "B";
        }
        else if (cen == c) {
            if (d[0][c] == 1) {
                ans = "A";
            }
            else {
                ans = "C";
            }
        }
        else {
            int x = d[0][cen];
            int y = d[1][cen];
            int z = d[2][cen];
            if (x < y && z >= x - 1) {
                ans = "A";
            }
            else if (y <= x && z >= y + 1) {
                ans = "B";
            }
            else if (x >= z + 2 && y >= z) {
                ans = "C";
            }
            else {
                ans = "DRAW";
            }
        }
        cout << ans << "\n";
    }
}