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.Scanner;
import java.math.BigInteger;
public class Test {
  public static void main(String[] args) {
    int m = 1;
    
    Scanner scanner = new Scanner(System.in);
    int n = scanner.nextInt();
    while(m<1000) {
        int result = n*m + 1; 
        if(isPrimeNumber(result)){
            m++;
        } else {
            break;
        }
    }
    System.out.println(m);
  }
  
  public static boolean isPrimeNumber(int number) {
      BigInteger bValue = BigInteger.valueOf(number);
      return bValue.isProbablePrime(1);
  }
}