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.HashSet;
import java.util.Scanner;

public class Contest755_A {
    static HashSet<Integer> comp = new HashSet<>();

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        sieve();
        for(int i = 1; i <= 1000; i++)
            if(comp.contains(n*i+1)) {
                System.out.println(i);
                break;
            }
    }

    public static void sieve() {
        int pr[] = new int[100000];

        for(int i = 2; i*i <= 10000; i++)
            if(pr[i] == 0)
                for(int j = 2*i; j <= 10000; j+=i)
                    pr[j] = 1;

        for(int i = 2; i < 10000; i++)
            if(pr[i] == 1)
                comp.add(i);
    }
}