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 = new int[n]; 
        int[] B = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            A[a0] = x;
            B[a0] = y;
        }
        boolean flagx = true, flagy = true;
        int firstx = A[0], firsty = B[0];
        for (int i = 1; i < n; i++) {
            if (A[i] != firstx) flagx = false;
            if (B[i] != firsty) flagy = false;
        }
        if (flagx == true || flagy == true) {
            System.out.println("YES");
        }else {
            System.out.println("NO");
        }
    }
}