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.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class Solution implements Runnable {
  BufferedReader in;
  PrintWriter out;
  StringTokenizer tok = new StringTokenizer("");

  @Override
  public void run() {
    try {
      init();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    }
    long time = System.currentTimeMillis();
    try {
      solve();
    } catch (Exception e) {
      e.printStackTrace();
    }
    out.close();
    //System.err.println(System.currentTimeMillis() - time);
  }

  private void init() throws FileNotFoundException {
    String file = "";
    if (!file.equals("")) {
      in = new BufferedReader(new FileReader("input.txt"));
      out = new PrintWriter("output.txt");
    } else {
      in = new BufferedReader(new InputStreamReader(System.in));
      out = new PrintWriter(System.out);
    }
  }

  public static void main(String[] args) {
    new Thread(new Solution()).start();
  }

  private String readString() {
    while (!tok.hasMoreTokens()) {
      try {
        tok = new StringTokenizer(in.readLine());
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return tok.nextToken();
  }

  private int readInt() {
    return Integer.parseInt(readString());
  }

  private long readLong() {
    return Long.parseLong(readString());
  }


  private void solve() {
    int n = readInt();
    if(n==1) {
      out.print(3);
      return;
    }
    if(n==2) {
      out.print(4);
      return;
    }
    out.print(n-2);
  }




}