import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int a=in.nextInt();
        int b=in.nextInt();
        boolean sameV=true;
        boolean sameH=true;
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if(x!=a)
            	sameV=false;
            if(y!=b)
            	sameH=false;
        }
        if(sameV||sameH)
        	System.out.print("YES");
        else
        	System.out.print("NO");
    }
}