#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> ti;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
#define all(x) (x).begin(),(x).end()
 
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n,s,t;cin>>n>>s>>t;
    vector<set<pi>> a(t+1);
    vector<pi> ans(n);
    REP(i,0,n){
        int x,y;cin>>x>>y;
        if(x==y){
            ans[i]={x,y};
            continue;
        }
        a[x].insert({y,i});
        a[y].insert({x,i});
    }
    REP(i,1,n+1){
        if(a[i].empty())continue;
        int p=1;
        while(!a[i].empty()){
            p=1-p;
            set<int> st;
            vi arr;
            int x=i;
            bool f=1;
            while(f){
                if(a[x].empty())break;
                st.insert(x);arr.PB(x);
                auto [y,z]=*a[x].begin();
                if(p%2==0)ans[z]={x,y};
                else ans[z]={y,x};
                a[x].erase({y,z});
                a[y].erase({x,z});
                if(st.count(y)){
                    while(arr.back()!=y){
                        st.erase(arr.back());
                        arr.pop_back();
                    }
                    st.erase(arr.back());
                    arr.pop_back();
                    if(arr.empty())break;
                }
                x=y;
            }
        }
    }
    for(auto [u,v]:ans)cout<<u<<" "<<v<<"\n";
}
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