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:
// package stupiddog;

import java.io.IOException;
import java.lang.*;
import java.util.Scanner;

/**
 *
 * @author Huỳnh Sâm Hà - BKU - 1610852@hcmut.edu.vn
 */
public class StupidDog {

    public static Scanner inp = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        int n = inp.nextInt();
        process: 
        for (int m = 1; m < 1000; m++) {
            int k = n*m+1;
            for (int i=2;i*i<=k;i++)
                if (k%i == 0) {
                    System.out.println(m);
                    break process; 
                }
        }
    }

}