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 PolandBallAndHypothesis {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int prime[]=new int[3005];
		for(int i=0;i<=3000;i++) {
			prime[i]=0;
		}
		prime[1]=0;
		prime[2]=1;
		for(int i=3;i<=3000;i=i+2) {
			prime[i]=1;
		}
		for(int i=3;i*i<=3000;i=i+2) {
			if(prime[i]==1) {
				for(int j=2*i;j<=3000;j=j+i) {
					prime[j]=0;
				}
			}
		}
		for(int i=1;i<=1000;) {
			int m=n*i+1;
			if(prime[m]==0) {
				System.out.println(i);
				break;
			}
			else {
				i++;
			}
		}
		
	}

}