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.*;

public class Main {

	public static void main(String[] args) {
		
		Scanner input = new Scanner(System.in);
		
		int n = input.nextInt();
		
		
		
		
		for (int i = 1; i >=1; i++) {
			
			int t = (n*i)+1;
			if (isprime(t)==false) {
				
				System.out.println(i);
				break;
			}
			
			
			
		}
		
		
		
		
		System.exit(0); input.close();

	}
	public static int sumofdigits(int n) 
    {     
    int sum = 0; 
      
    while (n != 0) 
    { 
        sum = sum + n % 10; 
        n = n/10; 
    } 
  
   return sum; 
} 
 
   public static int reversedigits(int num) 
    { 
    int rev_num = 0; 
    while(num > 0) 
    { 
        rev_num = rev_num * 10 + num % 10; 
        num = num / 10; 
    } 
    return rev_num; 
    } 
 
	public static int binarysearch(int arr[], int l, int r, int x) 
    { 
		
        if (r >= l) { 
            int mid = l + (r - l) / 2; 
            if (arr[mid] == x) 
                return mid; 
            if (arr[mid] > x) 
                return binarysearch(arr, l, mid - 1, x); 
            return binarysearch(arr, mid + 1, r, x); 
        }  
        return -1; 
    }
		
	public static int gcd(int a, int b)
	    {
	        if (a == 0)
	            return b; 
	        return gcd(b % a, a); 
	    }
	
	  public static int lcm (int a, int b)
	    {
	        return (a / gcd(a, b)) * b;
	    }
	    
	  public static void rangeofprimenumber(int a, int b) 
	    {  
	    	int i, j, flag;
	    	for (i = a; i <= b; i++) {
	            if (i == 1 || i == 0)
	                continue;
	            flag = 1;
	            for (j = 2; j <= i / 2; ++j) {
	                if (i % j == 0) {
	                    flag = 0;
	                    break;
	                }
	            }
	            if (flag == 1)
	                System.out.println(i);
	        }
	    } 
	  
	   public static boolean isprime(int n)
	    {
	        if (n <= 1)
	            return false;
	        else if (n == 2)
	            return true;
	        else if (n % 2 == 0)
	            return false;
	        for (int i = 3; i <= Math.sqrt(n); i += 2) 
	        {
	            if (n % i == 0)
	                return false;
	        }
	        return true;
	    }
	    
	   public static int factorial(int n) 
	    { 
	      return (n == 1 || n == 0) ? 1 : n * factorial(n - 1); 
	    } 
	   
	   public static int[] reversearrayinrange(int arr[],int start, int end)
             {
               int temp;
     
               while (start < end)
              {
                temp = arr[start]; 
                arr[start] = arr[end];
                arr[end] = temp;
                start++;
                end--;
              } 
               return arr;
       } 

}