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 ex13 {
    public static void main(String[]args){
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[1000 * n + 1];
        for (int i = 0; i <= 1000 * n; i++){
            a[i] = 1;
        }


        for (int i = 2; i <= 1000 * n; i++){
            if(a[i] == 1) {
                for(int j = i * 2; j <= 1000 * n; j += i)
                    a[j] = -1;
            }
        }
        if (n == 1) {
            System.out.println(3);
            return;
        }
        if (n == 2) {
            System.out.println(4);
            return;
        }
        for (int i = 0; i < n; i++){
            if (a[i * n + 1] == -1) {
                System.out.println(i);
                break;
            }
        }
    }
}