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.*;
public class poland
{
    public static void main(String args[])
    {
        Scanner in = new Scanner(System.in);
        long n = in.nextLong(),ans;int i=1;
        if(n%2==0||n==1)
        {
            ans = n+1;
          while(checkprime(ans))
          {
              i++;
              ans = n*i+1;
              
          }
          System.out.println(i);
        }
        else
        System.out.println("1");}
   
public static boolean checkprime(long n)
{
    for(int i = 2;i<n;i++)
    {
        if(n%i==0)
        {
            return false;
        }
    }
    return true;
}
}