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.*;
import java.lang.*;
import java.util.*;

public class Maain{

	public static int[] array;
	public static void primes(){
		int arr[] = new int[1002];
		arr[0]= 1;
		arr[1] = 1;
		for(int i = 2; i< Math.sqrt(1001)+ 1; i++){
			if(i != 2 && i % 2 == 0)
				continue;
			else{
				for(int j = 2; j< 1001/i + 1; j++){
					if(j*i < 1002)
						arr[j*i] = 1;
				}
			}
		}
		int count = 0;
		for(int k1 = 0; k1< 1002 ; k1++){
			if(arr[k1] == 0)
				count++;
		}	
		array = new int[count];
		int it = 0;
		for(int k2 = 0; k2< 1002 ; k2++){
			if(arr[k2] == 0){
				array[it] = k2;
				it++;
			}
		}	
	}
	
	public static int prime(int n){
		int p = -1;
		for(int i = 0; i< array.length; i++){
			if(n % array[i] != 0){
				p = array[i];
				break;
			}
		}
		return p;
	}	
	
	public static int inverse(int a, int p){
		int h =(int) Math.pow(a, p-2);
		return h % p ;
	}
	
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		if(n== 1 || n == 2){
		    if(n== 1)
		        System.out.println(3);
		    else 
		        System.out.println(4);
		}
		else{
    		primes();
    		int pr = prime(n);
    		int value = inverse(n % pr, pr)*(pr-1);
    		System.out.println(value % pr);
		}
	}
}