import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int c=0;
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            checkPoints(x,y);
        }
        if(c == n)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
    
    static void checkPoints(int x, int y)
    {
        if(x==0 || y ==0)    
            c++;
    }
}