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


int main() {
    int n;
    cin>>n;
    bool h=true,v=true;
    n--;
    int x,y,a,b;
    cin>>x>>y;
    while(n--){
        cin>>a>>b;
        if(a!=x)
            h = false;
        if(b!=y)
            v = false;
    }
    if(h|v)
        cout<<"YES";
    else
        cout<<"NO";
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}