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 sc=new Scanner(System.in);
     int x,y;
     int n=sc.nextInt();
     int[] X=new int[n];
     int[] Y=new int[n];
     for(int i=0;i<n;i++){
        x=sc.nextInt();
        X[i]=x;
        y=sc.nextInt();
        Y[i]=y;
     }
     for( int j=0;j<(n-2);j++){
         if((Y[j+1]-Y[j])*(X[j+2]-X[j+1])==(Y[j+2]-Y[j+1])*(X[j+1]-X[j])){
         continue;   
         }
         else{
            System.out.println("NO");
            System.exit(0);
         }
     }
    System.out.println("YES");
    }
}