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.util.*;
import java.math.BigInteger;

public class CodeForcesCompetetive {

	public static void main(String[] args) throws IOException,NumberFormatException {
		try {
			FastScanner sc=new FastScanner();
			
			int n=sc.nextInt();
			if(n==1) {
				System.out.println(3);
			}
			else if(n%2!=0) {
				System.out.println(1);
			}
			else {
				
				outer:for(int i=1;i<=1000;i++) {
						if(!isPrime(n*i+1)) {
							System.out.println(i);
							break outer;
					}
				}
			}
			
		}
		catch(Exception e) {
			return;
		}
	}
        public static boolean isPrime(int n) {
	    if(n==1) {
	    	return false;
	    }
	    for(int i=2;i*i<=n;i++) {
	    	if(n%i==0) {
	    		return false;
	    	}
	    }
	    return true;
	}
	
	public static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try { 
                                      st=new StringTokenizer(br.readLine());				               
                              } catch (IOException e) {}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		long nextLong() {
			return Long.parseLong(next());
		}
		
	}

}