#include <iostream>
#include <bits/stdc++.h>
using namespace std;
 
void dfs ( int n, vector < int > sasiad[],bool odwiedzone[]){
    odwiedzone[n] = true;
 
    for(int i=0;i<sasiad[n].size();i++){
 
        if(!odwiedzone[sasiad[n][i]]){
            cout<<" "<<sasiad[n][i];
            dfs(sasiad[n][i],sasiad,odwiedzone);
        }
    }
}
 
int main()
{
    int n;
    cin>>n;
    for(int e = 0;e<n;e++){
        int osob,wiadomosci,plotkarz,a,b;
        cin>>osob>>wiadomosci>>plotkarz;
 
        vector < int > sasiad[osob+1];
 
        bool start = false;
 
        bool *odwiedzone = new bool[osob+1];
 
        for(int i=0;i<wiadomosci;i++){
            cin>>a>>b;
            if(a == plotkarz) start = true;
            if(start) sasiad[a].push_back(b);
        }
 
        cout<<plotkarz;
        dfs(plotkarz,sasiad,odwiedzone);
        cout<<endl;
 
        delete []odwiedzone;
    }
    return 0;
}
 

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