#include <bits/stdc++.h>
using namespace std;
 
const int MaxN=2e5;
const int MaxT=2e5;
int add[MaxT+1]={};
struct LINE{
	int s, e;
	LINE(int s=0,int e=0):s(s),e(e){}
};
int main() {
	int N,S,T;
	cin>>N;
	for(int n=0;n<N;n++){
		cin>>S>>T;
		add[S]+=1;
		add[T]-=1;
	}
 
	vector<LINE> ans;
	int now=0;
	for(int t=1;t<=MaxT;t++){
		if(now==0 && now+add[t]>0)
			ans.push_back(LINE(t));
		if(now>0 && now+add[t]==0)
			ans.back().e=t;
		now+=add[t];
	}
	for(LINE one:ans)
		cout<<one.s<<" "<<one.e<<"\n";
	return 0;
}

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MwoxMCAyMAoyMCAzMAo0MCA1MA==

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