import java.util.Scanner;

public class PerfectNumber
{
   public static void main(String[] args) 
   {
       Scanner input = new Scanner(System.in);
       
       int x, sum, i;
       
       x = input.nextInt();
       
       sum = 0;

       for ( i = 1; i < x; i++ )
           if ( x%i == 0 )          // i is a divisor of x
               sum = sum + i;      // Add i to sum

       if ( sum == x )
           System.out.println("is a perfect number"); 
       else
           System.out.println("is not a perfect number"); 
   }
}