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.*;

/**
 * Created by Luis Ngo on 4/1/2017.
 */
public class PA {
    public static void main(String args[]){
        Scanner scanner = new Scanner (System.in);
        int n =  scanner.nextInt();
        for (int i = 1 ; i <=1000; i++){
            int result  = n*i +1;
            if  (!isPrime(result)){
                System.out.println(i);
                return;
            }
        }



    }
    //checks whether an int is prime or not.
    public static boolean isPrime(int n) {
        if (n == 4) return false;
        for(int i=2;2*i<n;i++) {
            if(n%i==0)
                return false;
        }
        return true;
    }
}