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][2];
        boolean yes=true;
        for(int a0 = 0; a0 < n; a0++){
            
            a[a0][0] = in.nextInt();
            a[a0][1] = in.nextInt();
            
        }
        
        if(a[0][0]>a[1][0])
            {
            int y=1;
            while(y<n-1 && yes)
                {
                if(a[y][0]<a[y+1][0])
                  yes=false;
                y++;
            }
        }
        if(a[0][0]<a[1][0])
            {
            int y=1;
            while(y<n-1 && yes)
                {
                if(a[y][0]>a[y+1][0])
                  yes=false;
                y++;
            }
        }
        
        if(a[0][0]==a[1][0])
            {
            int y=1;
            while(y<n-1 && a[y][0]==a[y+1][0])
                {
                if(a[y][0]<a[y+1][0])
                  yes=false;
                y++;
            }
            if(y<n-1 && a[y][0]!=a[y+1][0])
                {
                if(a[y][0]>a[y+1][0])
            {
            
            while(y<n-1 && yes)
                {
                if(a[y][0]<a[y+1][0])
                  yes=false;
                y++;
            }
        }
                if(a[y][0]<a[y+1][0])
            {
            
            while(y<n-1 && yes)
                {
                if(a[y][0]>a[y+1][0])
                  yes=false;
                y++;
            }
        }
                
            }
        }
        
        
        if(yes)
            System.out.println("YES");
        else
            System.out.println("NO");
        
    }
}