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 X = true;
        boolean Y = true;
        for(int i = 1;i<n;i++){
            X = X&(a[i] == a[i-1]);
            Y = Y&(b[i] == b[i-1]);
        }
        if(X || Y){
            System.out.println("YES");
            return;
        }
        System.out.println("NO");
    }
}