// Note that any question that asks you for floating point input may be very
// tricky.  Use integers unless you can't avoid it, and you should *never*
// output a floating point number using a straight System.out.println().
// For more information on String.format, see: 
// http://java.sun.com/j2se/1.5.0/docs/api/java/util/Formatter.html
import java.util.*;
import java.io.*;
public class div_seven {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    boolean first = true;
    while (in.hasNextInt()) {
      if (!first) System.out.println();
      else first = false;
      int n = in.nextInt();
      System.out.println(String.format("%1$.2f", n / (double)7));
    }
  }
}