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;

public class VC82017P1 {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		scan.nextLine(); 
		//DO YOU NEED LONGS FAGGIT
		boolean[] isPrime = new boolean[9000000];
        for (int i = 2; i < 9000000; i++) {
            isPrime[i] = true;
        }
        // mark non-primes <= n using Sieve of Eratosthenes
        for (int factor = 2; factor*factor < 10000000; factor++) {
            // if factor is prime, then mark multiples of factor as nonprime
            // suffices to consider mutiples factor, factor+1, ...,  n/factor
            if (isPrime[factor]) {
                for (int j = factor; factor*j < 9000000; j++) {
                    isPrime[factor*j] = false;
                }
            }
        }
        int ans = 0;
        for(int i = 1; i <= 1000; i++){
        	ans = n*i+1;
        	if(!isPrime[ans]){
        		System.out.println(i);
        		break;
        	}
        }
	}
}