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.Scanner;

/**
 * Created by Marcin on 15.01.2017.
 */
public class PolandBall8vcCup2017 {
    public static boolean prime(int n){
        if(n>2){
            double sq = Math.sqrt(n);
            if (n%2==0){
                return false;

            }else {
                for (int i = 3; i <= sq ; i+=2) {
                    if(n%i==0){
                        return false;
                    }
                }
                return true;
            }
        }else if (n==2)return true;
        return false;
    }

    public static void main(String[] args) {
        int number,answer,counter;
        counter = 1;
        Scanner input = new Scanner(System.in);
        number = input.nextInt();

        for (int i = 1; i <1000 ; i++) {
            answer =  number * i + 1 ;
            if (prime(answer)) {
                counter++;
            }else break;
        }
        System.out.println(counter);
    }
}