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();
        boolean isVertical = in.nextInt() == 0;
        boolean isHorizontal = in.nextInt() == 0;
        for(int a0 = 0; a0 < n-1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if ((isVertical && x != 0) || (isHorizontal && y != 0)) {
                System.out.println("NO");
                return;
            }
        }
        System.out.println("YES");
    }
}