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.io.PrintWriter;
import static java.lang.System.out;
import java.util.Random;
import java.util.Scanner;
import java.util.Arrays;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.util.StringTokenizer;

/**
 *
 * @author fatsu
 */
public class JavaApplication7 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        //Random rand = new Random();
        Scanner read = new Scanner(System.in);
        int reader = read.nextInt();
        //int reader = rand.nextInt(999) + 1;

//        System.out.println(reader);
        int result;

        if (reader == 1) {
            result = 5;
        } else if (reader == 2) {
            result = 4;
        } else if (reader % 2 == 1) {
            result = 3;
        } else if (reader == 998) {
            result = 3;
        } else if (reader == 1000) {
            result = 2;
        } else {
            result = reader + 2;
        }

//        System.out.println(result);
//        System.out.println(reader*result + 1);
        out.print(result);
        out.close();
    }

}