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 iN = in.nextInt();
        int[] aArrayX = new int[iN];
        int[] aArrayY = new int[iN];
        for ( int i = 0; i < iN; i++ ) {
            aArrayX[i] = in.nextInt();
            aArrayY[i] = in.nextInt();
        }
        in.close();

        boolean bResult = true;
        int iX = aArrayX[0];
        int i = 1;
        while ( i < iN && bResult ) {
            bResult = (aArrayX[i] == iX);
            i++;
        }

        if ( !bResult ) {
            bResult = true;
            int iY = aArrayY[0];
            i = 1;
            while ( i < iN && bResult ) {
                bResult = (aArrayY[i] == iY);
                i++;
            }
        }

        System.out.println(bResult ? "YES" : "NO");

    }
}