Problem: PolandBall is a young, clever Ball. He is interested in prime numbers. He has stated a following hypothesis: "There exists such a positive integer n that for each positive integer m number n·m + 1 is a prime number".

Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any n.

Input

The only number in the input is n (1 ≤ n ≤ 1000) — number from the PolandBall's hypothesis. 

Output

Output such m that n·m + 1 is not a prime number. Your answer will be considered correct if you output any suitable m such that 1 ≤ m ≤ 103. It is guaranteed the the answer exists.

Examples

Input

3


Output

1

Input

4


Output

2

Note

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

For the first sample testcase, 3·1 + 1 = 4. We can output 1.

In the second sample testcase, 4·1 + 1 = 5. We cannot output 1 because 5 is prime. However, m = 2 is okay since 4·2 + 1 = 9, which is not a prime number.

Solution (in JAVA):

Solution:
import java.lang.*;
import java.util.*;
import java.io.*;
public class test
{  
  Scanner sc=new Scanner(System.in);
  PrintWriter pr=new PrintWriter(System.out,true);
  public static void main(String... args) 
  {
       test c=new test();
       c.prop();
  }
  public void prop() 
  {
    int n,m=0,x;
    n=sc.nextInt();
     double d=0 ;
       for (int i=1; ;++i) {
          x=n*i+1 ;
          m=x ;
          d=0.0+x ;
          d=Math.sqrt(d);
          x=(int)d ;
             if(m>3){
             for (int j=2;j<=x ;++j) {
                  if(m%j==0)
                     {
                      m=i ;
                      break ;
                     }
                     if(j==x)
                       m=0 ;
             }
            }else
               m=0 ; 
           if(m!=0)
             { pr.println(m); break ; }
            
       }
     
        
  }
}