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[] xc= new boolean [25];
        boolean[] yc= new boolean [25];
        
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            
           
            if(y<0){
                y= Math.abs(y);
            }
            else if(y==0){
                y=11;
            }
            else if(y>=1){
                y+=11;
            }
            
            if(x>=1){
                x+=11;
            }
            else if(x<0){
                x= Math.abs(x);
            }
            else if(x==0){
                x=11;
            }
           
            xc[x]= true;
            yc[y]= true;
        }
        
        int countx= 0, county=0;
        for(int i=0; i<25; i++){
            if(xc[i]==true){
                countx++;
            }
            
            if(yc[i]==true){
                county++;
            }
        }
        
        if(countx==1 && county==n){
            System.out.println("YES");
        }
        else if(county==1 && countx==n){
            System.out.println("YES");
        }
        else{
            System.out.println("NO");
        }
    }
}