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.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner cin = new Scanner(System.in);
		Boolean composite[] = new Boolean[1000002];
		for(int i = 2; i < 1000001; ++i)
			composite[i]=false;
		composite[1] = true;
		int prime[] = new int[1000001];
		int num = 0;
		for(int i = 2; i < 1000001; ++i){
			if(!composite[i]){
				prime[num++]=i;
			}
			for(int j = 0; j < num && i*prime[j] < 1000001; ++j){
				composite[i*prime[j]]=true;
				if(i%prime[j] == 0) break;
			}
		}
		while(cin.hasNext()){
			int n = cin.nextInt();
				for(int i = 1; i < 1001; ++i){
					if(composite[n*i+1]){
						System.out.println(i);
						break;
					}
				}
			}
	}

}