#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;
    bool vertical = true; bool horizontal =true;
    int x0,y0; cin >> x0 >> y0;
    for ( int i = 0; i <n; i++){
        int x,y; cin >> x>> y;
        if ( x != x0) horizontal = false;
        if ( y != y0) vertical = false;
    }
    if(horizontal ||vertical){
        cout << "YES"<<endl;
    }
    else{
        cout <<"NO" <<endl;
    }
    return 0;
}