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 x = in.nextInt();
            int y = in.nextInt();
        int storex=x,storey=y,flagx=0,flagy=0;
        for(int a0 = 0; a0 < n-1; a0++){
            x = in.nextInt();
            y = in.nextInt();
            if(storex==x) flagx++;
            if(storey==y) flagy++;
        }
        if(flagx==n-1 || flagy==n-1) System.out.print("YES");
        else System.out.print("NO");
    }
}