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:
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/*
 * @author Rohini Chandra
 */
import java.util.*;
import java.io.*;
public class ROUGH{
    public static void main(String args[]) throws IOException{
       /*BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       PrintWriter pw = new PrintWriter(System.out);*/
       //List<Integer> list = new ArrayList<>();
       //Map<Integer,Integer> map = new HashMap<>();
       //Set<Integer> set = new HashSet<>();
       Scanner sc = new Scanner(System.in);
       int n = sc.nextInt();
       int m=0;
       if(n==2)
          m=4;
       else if(n==1)
          m=3; 
       else{
          m=n-2;
       }
       System.out.print(m);
    }
                                        //******** PRINT ********//
    static void prt(int a){
       System.out.print(a);
    }
                                       //******** PRINTLN ********//
    static void prtl(int b){
       System.out.println(b); 
    }         
                                       //******** FACTORIAL ********//
    static int fact(int n){
       if(n==1)
          return 1;
       else
          return n*fact(n-1);
    }
                                       //******** OCCURRENCE ********//
    static Map<String,Integer> ocr(String str[]){
           Map<String,Integer> map = new HashMap<>();
           for(int i=0; i<str.length; i++){
           if(!map.containsKey(str[i]))
              map.put(str[i], 1);
           else
              map.put(str[i], map.get(str[i])+1);
           }
           return map;
    }
                                        //******** PRIME OR NOT ********//
    static boolean isprime(long num){
        if(num<=1)
            return false;
        else if(num<=3)
            return true;
        else if(num%2==0 || num%3==0)
            return false;
        else{
            for(int i=5; i*i<=num; i+=6){
                if(num%i==0 || num%(i+2)==0)
                   return false; 
            }
            return true;
        }
    }
                                       //******** GCD ************//
    static long gcd(long a, long b){
         if(b==0)
            return a;
         else if(a==0)
            return b;  
         else if(a>b)
            gcd(a%b,b);
         else if(a<b)
            gcd(a,b%a);
         else if(a==b)
            return a;
         return 0;
    }
}