#include<bits/stdc++.h>
using namespace std;
#define N 200005
int n,a,b,c;
vector<int> G[N];
int dep[N],fa[N];
void dfs1(int u,int fa)
{
	dep[u]=dep[fa]+1;
	::fa[u]=fa;
	for(int v:G[u])
	{
		if(v==fa) continue;
		dfs1(v,u);
	}
}
int lca(int u,int v)
{
	while(dep[u]!=dep[v])
	{
		if(dep[u]>dep[v]) u=fa[u];
		else v=fa[v];
	}
	while(u!=v) u=fa[u],v=fa[v];
	return u;
}
void work()
{
	scanf("%d%d%d%d",&n,&a,&b,&c);
	for(int i=1;i<=n;i++) G[i].clear(),fa[i]=0,dep[i]=0;
	for(int i=1;i<n;i++)
	{
		int u,v; scanf("%d %d",&u,&v);
		G[u].push_back(v),G[v].push_back(u);
	}
	dfs1(a,0);
	if(dep[c]-dep[a]==1) printf("A\n");
//	else if((L==b||L==c)&&abs(dep[b]-dep[c])==1) printf("B\n");
	else
	{
		int L=lca(b,c);
		int da=dep[L]-dep[a],db=dep[b]-dep[L],dc=dep[c]-dep[L];
		int wina=(da<db)&&(da<dc+2);
		int winb=(db<dc)&&(db<=da);
		int winc=(dc<=da-2)&&(dc<=db);
		assert(wina+winb+winc<=1);
		if(wina) printf("A\n");
		else if(winb) printf("B\n");
		else if(winc) printf("C\n");
		else printf("DRAW\n");
	}
}
signed main()
{
#ifdef xay5421
	freopen("a.in","r",stdin);
#endif
	int T; cin>>T; while(T--) work();
	return 0;
}