#include <iostream>
#include <algorithm>
#include<cmath>
#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<iomanip>
#include<ctime>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<bitset>
#include<cassert>
#include<random>
#define sqr(x) ((x)*(x))
#define fz1(i,n) for ((i)=1;(i)<=(n);(i)++)
#define fd1(i,n) for ((i)=(n);(i)>=1;(i)--)
#define fz0g(i,n) for ((i)=0;(i)<=(n);(i)++)
#define fd0g(i,n) for ((i)=(n);(i)>=0;(i)--)
#define fz0k(i,n) for ((i)=0;(i)<(n);(i)++)
#define fd0k(i,n) for ((i)=(((long long)(n))-1);(i)>=0;(i)--)
#define fz(i,x,y) for ((i)=(x);(i)<=(y);(i)++)
#define fd(i,y,x) for ((i)=(y);(i)>=(x);(i)--)
#define fzin fz1(i,n)
#define fzim fz1(i,m)
#define fzjn fz1(j,n)
#define fzjm fz1(j,m)
#define ff(c,itr) for (__typeof((c).begin()) itr=(c).begin();itr!=(c).end();++itr)
#define pb push_back
#define mk make_pair
#define rdst(st,len){static char ss[len];scanf(" %s",ss);(st)=ss;}
#define spln(i,n) (i==n?'\n':' ')
#define fac_init(n){fac[0]=fac[1]=inv[1]=fi[0]=fi[1]=1;fz(i,2,n){fac[i]=1ll*fac[i-1]*i%mod;inv[i]=1ll*(mod-mod/i)*inv[mod%i]%mod;fi[i]=1ll*fi[i-1]*inv[i]%mod;}}
using namespace std;
typedef long long i64;
typedef long double f80;
typedef unsigned int u32;
typedef unsigned long long u64;
inline void read(int &x)
{
	char c;int f=1;
	while(!isdigit(c=getchar()))if(c=='-')f=-1;
	x=(c&15);while(isdigit(c=getchar()))x=(x<<1)+(x<<3)+(c&15);
	x*=f;
}
int tt,n,m,s,t,i,j,lg[50005],dep[50005],dfn[50005],mp[50005],ti,f[16][50005];
vector<int> bi[50005];
void dfs(int x,int fa)
{
	mp[dfn[x]=++ti]=x;f[0][ti]=dep[fa];
	ff(bi[x],it)if(*it!=fa)dep[*it]=dep[x]+1,dfs(*it,x); 
}
int dlca(int x,int y)
{
	if(x==y)return dep[x];x=dfn[x];y=dfn[y];
	if(x>y)swap(x,y);x++;int t=lg[y-x+1];
	return min(f[t][x],f[t][y-(1<<t)+1]); 
}
int dis(int x,int y){return dep[x]+dep[y]-2*dlca(x,y);}
mt19937 rnd(1064);
void solve()
{
	read(n);read(s);read(t);
	fz1(i,n)bi[i].clear();
	fz1(i,n-1){
		int x,y;read(x);read(y);
		bi[x].push_back(y);
		bi[y].push_back(x);
	}
	ti=0;dfs(1,0);
	fz1(j,lg[n])fz1(i,n-(1<<j)+1) f[j][i]=min(f[j-1][i],f[j-1][i+(1<<(j-1))]);
	vector<int> v,res;int ans=4;
	v.push_back(s);
	fz1(i,n)if(i!=s&&i!=t)v.push_back(i);
	v.push_back(t);
	int cur=0;fz1(i,v.size()-1) cur^=dis(v[i-1],v[i]);
	if(cur<ans) ans=cur,res=v;
	int _=n*200;
	while(n>3&&_--&&ans>1){
		int x=rnd()%(n-2)+1;
		int y=rnd()%(n-3)+1;
		y+=(y>=x);
		cur^=dis(v[x],v[x-1]);
		cur^=dis(v[x],v[x+1]);
		cur^=dis(v[y],v[y-1]);
		cur^=dis(v[y],v[y+1]);
		swap(v[x],v[y]);
		cur^=dis(v[x],v[x-1]);
		cur^=dis(v[x],v[x+1]);
		cur^=dis(v[y],v[y-1]);
		cur^=dis(v[y],v[y+1]);
		if(cur<ans) ans=cur,res=v;
	}
	assert(ans<4);
//	printf("%d\n",ans);
	ff(res,it)printf("%d ",*it);puts("");
}
int main()
{
	fz(i,2,50000)lg[i]=lg[i/2]+1;
	read(tt);
	while(tt--) solve();
	return 0;
}