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 PolandBallAndHypothesis {
public static void main(String[] args) throws NumberFormatException, IOException {
	BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
	int Prime[]=new int[1000002];
	
	Prime[0]=Prime[1]=1;
	for(int p=2;p*p<=1000001;p++){
		if(Prime[p]==0){
			for(int j=p*2;j<1000002;j=j+p){
				Prime[j]=1;
			}
		}
	}
	long N=Long.parseLong(br.readLine());
	
	for(int i=1;i<=1000;i++){
		long x=N*i+1;
		if(Prime[(int)x]==1){
			System.out.println(i);
			break;
		}
	}
	
}
}