#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int n ;
    cin>>n;
    int x,y ,xx,yy,f1=1,f2=1;
    cin>>x>>y ;
    n-- ;
    while(n--){
        cin>>xx>>yy ;
        if(x!=xx) f1=0 ;
        if(y!=yy) f2=0 ;
    }
    if(f1 || f2) cout<<"YES\n" ;
    else cout<<"NO\n" ;
    return 0;
}