#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define dd double
#define ld long double
#define pi 3.14159265359
#define ull unsigned long long
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define el "\n"
#define Arwa ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define fix(x) cout<<fixed<<setprecision(x)
ll gcd(ll a,ll b) {return b==0?a:gcd(b,a%b);}
ll lcm(int a,int b) {return a/gcd(a,b)*b;}
bool prime(ll n)
{
if(n==2) return true;
if(n%2==0||n==1) return false;
else { for(ll i=3; i*i<=n; i+=2) {if(n%i==0) return false;}}return true;
}
//here we go again
bool comp(pair<int,int>a,pair<int,int>b)
{
return a.first<b.first;
return a.second<b.second;
}
int main()
{
Arwa
int t=1;
//cin>>t;
while(t--)
{
int n;
cin>>n;
pair<ll,ll> arr[n];
for(int i=0;i<n;i++)
cin>>arr[i].first>>arr[i].second;
for(int i=0;i<n;i++)
{
if(arr[i].first>arr[i].second)
swap(arr[i].first,arr[i].second);
}
sort(arr,arr+n,comp);
//for(int i=0;i<n;i++)
//cout<<arr[i].first<<' '<<arr[i].second<<el;
int min=arr[0].first,max=arr[0].second;
for(int i=0;i<n;i++)
{
if(arr[i].first==arr[i+1].first)
i++;
if(i-1>=0)
{
if(arr[i].first>arr[i-1].second)
{
max=arr[i-1].second;
cout<<min<<' '<<max<<el;
min=arr[i].first;
}
}
if(arr[i].second>max)
max=arr[i].second;
}
cout<<min<<' '<<max<<el;
}
return 0;
}
/*
5
1 2
1 3
4 6
5 9
*/
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