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 cc;

import java.util.Scanner;

public class CF_1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int p=0;
		for(int i=1;i<1000;i++)
		{
			p = n*i+1;

				if(!new SC_CF_1().prime(p))
				{	
					System.out.println(i);
					return;
				}
		}
	}

}
class SC_CF_1{
	boolean prime(int p)
	{	

			if(p==1) 
				return false;
			else if(p==2) 
				return true;
			for(int i=2;i*i<=p;i++)
			{	if(p%i==0)
					return false;
			}
				return true;
		
	}
}