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 ank;

import java.util.Scanner;

public class jan15 {
	public static void main(String[] args) {
		Scanner scnr=new Scanner(System.in);
		int n=scnr.nextInt();
		int c=1000000+5;
		int ar[]=new int[1000000+5];
		ar[1]=1;
		for(int i=2;i<c;i++)
		{
			if(ar[i]==0)			{
				int k=2*i;
				while(k<c)
				{
					ar[k]=i;
					k=k+i;
					
				}
				
			}
			
		}
		for(int i=1;i<1000+1;i++)
		{
			if(ar[n*i+1]!=0)
			{
				System.out.println(i);
				return ;
			}
		}
		
		
	}

}