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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class codeforces {
    
    public static BufferedReader in = new   BufferedReader(new InputStreamReader(System.in)); 

    public static void cargarArray() throws IOException {

        int n = Integer.parseInt(in.readLine());
        int[] num = new int[n];
        
        String []strNums = in.readLine().split("\\s");
        
       for(int i=0; i<n; i++) {
            num[i] = Integer.parseInt(strNums[i]) - 1;
        }

        boolean ans = false;

        for (int i=0; i<n; i++){
            if (num[num[num[i]]] == i){
                ans = true;
                break;
            } 
        }        
        System.out.println(ans ? "YES" : "NO");

    }

    public static void main(String[] args) throws IOException {
        
        int n = Integer.parseInt(in.readLine());
        int[] num = new int[n];

        if (n%2==1){
            System.out.println(3);
        }else if(n==2){
            System.out.println(4);
        }else{
            System.out.println(n-2);
        }
    }

}