#include<bits/stdc++.h> using namespace std; int v[2005][2005],n,x,y; int main(){ cin>>n; memset(v,0,sizeof(v)); for(int i=1;i<=n;i++){ cin>>x>>y; v[x][y]++; } for(int i=1;i<=1000;i++)for(int j=1;j<=1000;j++) while(v[i][j]){ v[i][j]--; cout<<i<<" "<<j<<endl; } return 0; }