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

class Code {

	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		String[] str = br.readLine().split(" ");
		int x = Integer.parseInt(str[0]);
		int y = Integer.parseInt(str[1]);
		boolean flag1=true,flag2=true;
		
		for(int i=1;i<n;i++){
			str = br.readLine().split(" ");
			if(Integer.parseInt(str[0]) != x){
				flag1 = false;
			}
			if(Integer.parseInt(str[1]) != y){
				flag2 = false;
			}
		}
		if(flag1 || flag2){
			System.out.println("YES");
		}
		else{
			System.out.println("NO");
		}
		
	}
}