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.util.*;
  import java.io.*;
  
  public class Main {
    public static void main(String args[]) throws IOException {
      
      //write your code here
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      
      for(int m = 1;m<=1000;m++){
          int a = n*m+1;
          if(a==2 || a==3 || a==5 || a==7 || a==11 || a%13==0 || a%17==0 || a%19==0 || a%23==0 || a%29==0 ||  a%31==0 || a%37==0){
              continue;
          }else if(a%2==0 || a%3==0 || a%5==0 || a%7==0  || a%11==0 || a%13==0 || a%17==0 || a%19==0 || a%23==0 || a%29==0 ||  a%31==0 || a%37==0){
              System.out.println(m);
              break;
          }
      }
    }
  }