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 test;

import java.util.Scanner;

public class starter {

	

	public static void main(String[] args)
		throws Exception {
		
		Scanner conio = new Scanner ( System.in ) ;
		int n = conio.nextInt() , z = 0 ;
		
		if( n % 2 != 0 && n != 1 ) // odd 
			System.out.println(1) ;
		
		else
		{
			task : for ( int m = 1 ; m <= 1000 ; ++m )
			{
				z = n*m + 1 ;
				
				for ( int i = 2 ; i <= ( int ) Math.sqrt(z) ; ++i )
					if ( z % i == 0 )
					{
						z = m ;
						break task ;
					}
			}
			System.out.println(z); 
		}
		
		
			
			
		
		conio.close();
	}
	
	
}