import java.util.*;
import java.io.*;
/**
 * Write a description of class SemiPrimes here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class SemiPrimes
{
    public void main() throws Exception
    {
        int[] num_factors = new int[100];
        String fin = "DATA1.txt";
        String fout = "OUT1.txt";
        Scanner infile = new Scanner (new File(fin));
        PrintWriter outfile = new PrintWriter(new BufferedWriter(new FileWriter(fout)));
        int semiprime;
        
        int counter = 0;
        int count_primes = 0;
        
        while(infile.hasNextLine()) //repeat while not end of file
        {
            semiprime = infile.nextInt();
            
            for (int index = 2; index <semiprime; index++)
            {
                if (semiprime%index == 0)
                {
                    num_factors[counter] = index;
                    counter++;
                }
            }
            
            count_primes = 0;
                for (int x = 0; x < num_factors.length; x++)
                {
                    counter = 0;
                    for (int index = 1; index <= num_factors[x]; index++)
                    {
                        if (num_factors[x]%index == 0)
                        {
                            counter++;
                        }
                    }
                    if (counter == 2)
                    {
                        count_primes++;
                    }
                }

            if (count_primes == 3)
            {
                outfile.println("valid");
            }
            else
            {
                outfile.println("not");
            }
        }
        outfile.close();
        
        
        
    }
}