#include<bits/stdc++.h>

using namespace std;

map<int, int> xcoor;
map<int, int> ycoor;

int main()
{
    int i,j,k,l,m,n,o,p,q,r,s,t;
    cin>>n;
    o = n;
    while(o--)
    {
        cin>>i>>j;
        xcoor[i]++;
        ycoor[j]++;
        m=i;k=j;
    }
    if(xcoor[m]==n || ycoor[k]==n)
    {
        cout<<"YES";// "<<xcoor[m]<<" "<<ycoor[k];
    }
    else
        cout<<"NO";// "<<xcoor[m]<<" "<<ycoor[k];
    return 0;
}