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;
import java.io.*;

public class Gym {
    
    public static final int MX = (int) (1e6 + 5);
    
    public static int[] prime = new int[MX]; 
    
    public static void init() {
        int x,i,j;
        for (i = 0; i < MX; i++) {
            prime[i] = 0;
        }
        for (i = 4; i < MX; i+=2) {
            prime[i] = 1;
        }
        for (i = 3; i * i <= MX; i+=2) {
            if (prime[i] == 0) {
                for (j = i * i; j < MX; j+=i) {
                    prime[j] = 1;
                }
            }
        }
    }
    
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        //PrintWriter writer = new PrintWriter(System.out);
        init();
        int n,m,i,j;
        //System.out.println("Raihan");
        //System.out.println("RAIHAN");
        n = in.nextInt();
        for (i = 1; i <= 1000; i++) {
            m = n * i + 1;
            if (prime[m] == 1) {
                System.out.println(i);
                return;
            }
        }
        return;
    }
}