// ---------- begin Heavy-Light decomposition ----------
pub struct HLD {
    size: usize,
    edge: Vec<(usize, usize)>,
    child: Vec<Vec<usize>>,
    path_root: Vec<usize>,
    parent: Vec<usize>,
    left: Vec<usize>,
    right: Vec<usize>,
    inverse: Vec<usize>,
}

impl HLD {
    pub fn new(size: usize) -> Self {
        assert!(size <= 10usize.pow(8));
        HLD {
            size: size,
            edge: Vec::with_capacity(size - 1),
            child: Vec::new(),
            path_root: Vec::new(),
            parent: Vec::new(),
            left: Vec::new(),
            right: Vec::new(),
            inverse: Vec::new(),
        }
    }
    pub fn add_edge(&mut self, a: usize, b: usize) {
        assert!(a != b && a < self.size && b < self.size);
        self.edge.push((a, b));
    }
    pub fn build(&mut self, root: usize) {
        assert!(self.edge.len() + 1 == self.size);
        let size = self.size;
        let mut cnt = vec![0; size];
        for &(a, b) in self.edge.iter() {
            cnt[a] += 1;
            cnt[b] += 1;
        }
        let mut child = cnt
            .into_iter()
            .map(|c| Vec::with_capacity(c))
            .collect::<Vec<_>>();
        for &(a, b) in self.edge.iter() {
            child[a].push(b);
            child[b].push(a);
        }
        let mut parent = vec![size; size];
        let mut q = Vec::with_capacity(size);
        q.push(root);
        parent[root] = root;
        for i in 0..size {
            let v = q[i];
            for u in child[v].clone() {
                assert!(parent[u] == size);
                parent[u] = v;
                child[u].retain(|e| *e != v);
                q.push(u);
            }
        }
        let mut sum = vec![1; size];
        for &v in q.iter().rev() {
            let child = &mut child[v];
            if !child.is_empty() {
                let (pos, _) = child.iter().enumerate().max_by_key(|p| sum[*p.1]).unwrap();
                child.swap(0, pos);
                sum[v] = 1 + child.iter().fold(0, |s, a| s + sum[*a]);
            }
        }
        let mut path_root = (0..size).collect::<Vec<_>>();
        let mut left = vec![0; size];
        let mut right = vec![0; size];
        let mut dfs = vec![(root, false)];
        let mut id = 0;
        while let Some((v, end)) = dfs.pop() {
            if end {
                right[v] = id;
                continue;
            }
            left[v] = id;
            id += 1;
            dfs.push((v, true));
            let child = &child[v];
            if !child.is_empty() {
                for &u in child[1..].iter() {
                    path_root[u] = u;
                    dfs.push((u, false));
                }
                let u = child[0];
                path_root[u] = path_root[v];
                dfs.push((u, false));
            }
        }
        let mut inverse = vec![size; size];
        for (i, l) in left.iter().enumerate() {
            inverse[*l] = i;
        }
        self.child = child;
        self.parent = parent;
        self.left = left;
        self.right = right;
        self.path_root = path_root;
        self.inverse = inverse;
    }
    pub fn lca(&self, mut a: usize, mut b: usize) -> usize {
        assert!(a < self.size && b < self.size);
        let path = &self.path_root;
        let parent = &self.parent;
        let index = &self.left;
        while path[a] != path[b] {
            if index[a] > index[b] {
                std::mem::swap(&mut a, &mut b);
            }
            b = parent[path[b]];
        }
        std::cmp::min((index[a], a), (index[b], b)).1
    }
    pub fn path(
        &self,
        src: usize,
        dst: usize,
        up: &mut Vec<(usize, usize)>,
        down: &mut Vec<(usize, usize)>,
    ) {
        assert!(src < self.size && dst < self.size);
        up.clear();
        down.clear();
        let path = &self.path_root;
        let parent = &self.parent;
        let index = &self.left;
        let mut x = src;
        let mut y = dst;
        while path[x] != path[y] {
            if index[x] > index[y] {
                let p = path[x];
                assert!(p == path[p]);
                up.push((index[p], index[x] + 1));
                x = parent[p];
            } else {
                let p = path[y];
                assert!(p == path[p]);
                down.push((index[p], index[y] + 1));
                y = parent[p];
            }
        }
        if index[x] <= index[y] {
            down.push((index[x], index[y] + 1));
        } else {
            up.push((index[y], index[x] + 1));
        }
        down.reverse();
    }
    pub fn sub_tree(&self, v: usize) -> (usize, usize) {
        assert!(v < self.size);
        (self.left[v], self.right[v])
    }
    pub fn parent(&self, v: usize) -> Option<usize> {
        assert!(v < self.size);
        let p = self.parent[v];
        if p == v {
            None
        } else {
            Some(p)
        }
    }
    // s -> t へのパスの2番目の頂点を返す
    pub fn next(&self, s: usize, t: usize) -> usize {
        assert!(s < self.size && t < self.size && s != t);
        let (a, b) = self.sub_tree(s);
        let (c, d) = self.sub_tree(t);
        if !(a <= c && d <= b) {
            return self.parent[s];
        }
        let mut pos = t;
        let mut pre = t;
        while self.path_root[s] != self.path_root[pos] {
            pre = self.path_root[pos];
            pos = self.parent[pre];
        }
        if s == pos {
            pre
        } else {
            self.child[s][0]
        }
    }
    pub fn vertex(&self, x: usize) -> usize {
        assert!(x < self.size);
        self.inverse[x]
    }
    pub fn jump(
        &self,
        s: usize,
        t: usize,
        mut k: usize,
        up: &mut Vec<(usize, usize)>,
        down: &mut Vec<(usize, usize)>,
    ) -> Option<usize> {
        assert!(s.max(t) < self.size);
        self.path(s, t, up, down);
        for (l, r) in up.drain(..) {
            if k < r - l {
                return Some(self.vertex(r - 1 - k));
            }
            k -= r - l;
        }
        for (l, r) in down.drain(..) {
            if k < r - l {
                return Some(self.vertex(l + k));
            }
            k -= r - l;
        }
        None
    }
}
// ---------- end Heavy-Light decomposition ----------
// ---------- begin scannner ----------
#[allow(dead_code)]
mod scanner {
    use std::str::FromStr;
    pub struct Scanner<'a> {
        it: std::str::SplitWhitespace<'a>,
    }
    impl<'a> Scanner<'a> {
        pub fn new(s: &'a String) -> Scanner<'a> {
            Scanner {
                it: s.split_whitespace(),
            }
        }
        pub fn next<T: FromStr>(&mut self) -> T {
            self.it.next().unwrap().parse::<T>().ok().unwrap()
        }
        pub fn next_bytes(&mut self) -> Vec<u8> {
            self.it.next().unwrap().bytes().collect()
        }
        pub fn next_chars(&mut self) -> Vec<char> {
            self.it.next().unwrap().chars().collect()
        }
        pub fn next_vec<T: FromStr>(&mut self, len: usize) -> Vec<T> {
            (0..len).map(|_| self.next()).collect()
        }
    }
}
// ---------- end scannner ----------

use std::collections::*;
use std::io::Write;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn main() {
    use std::io::Read;
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut sc = scanner::Scanner::new(&s);
    let out = std::io::stdout();
    let mut out = std::io::BufWriter::new(out.lock());
    run(&mut sc, &mut out);
}

fn run<W: Write>(sc: &mut scanner::Scanner, out: &mut std::io::BufWriter<W>) {
    let t: u32 = sc.next();
    for _ in 0..t {
        let n: usize = sc.next();
        let a = sc.next::<usize>() - 1;
        let b = sc.next::<usize>() - 1;
        let c = sc.next::<usize>() - 1;
        let mut hld = HLD::new(n);
        for _ in 1..n {
            let a = sc.next::<usize>() - 1;
            let b = sc.next::<usize>() - 1;
            hld.add_edge(a, b);
        }
        hld.build(0);
        let mut up = vec![];
        let mut down = vec![];
        let mut dist = |x: usize, y: usize| -> usize {
            hld.path(x, y, &mut up, &mut down);
            up.iter()
                .chain(down.iter())
                .map(|p| p.1 - p.0)
                .sum::<usize>()
                - 1
        };
        let ans = (|| {
            if dist(a, c) == 1 {
                return "A";
            }
            if dist(b, a) == 1 {
                return "B";
            }
            let mid = hld.lca(a, b) ^ hld.lca(b, c) ^ hld.lca(c, a);
            if mid == a {
                return "A";
            }
            if mid == b {
                return "B";
            }
            if mid == c {
                return "C";
            }
            let x = dist(a, mid);
            let y = dist(b, mid);
            let z = dist(c, mid);
            if x <= z && x < y {
                return "A";
            }
            if y <= x && y < z {
                return "B";
            }
            if z <= y && z + 1 < x {
                return "C";
            }
            "DRAW"
        })();
        writeln!(out, "{}", ans).ok();
    }
}