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.*;
import java.io.*;
public class a{
	public static void main(String []args)throws Exception {
		BufferedReader sc=new BufferedReader(new InputStreamReader(System.in));
PrintWriter out=new PrintWriter(System.out);
	int test=Integer.parseInt(sc.readLine()),c=0,temp=0,k=0;
	for(int i=1;i<=1000;i++) {
		if((prime((test*i)+1)==false)) {
			out.println(i);
out.flush();
break;
			
		}
		
	}
	}
	static boolean prime(int a) {
		int c=0;
		for(int i=2;i<a;i++) {
			if(a%i==0)
			c++;
		}
		if(c==0)
			return true;
		else 
			return false;
	
	}
	
}