import java.util.Scanner;

/**
   Determines the average number of characters for words in a string.
   Input: a string of one or more lines containing words
   Output: the average number of characters per word in the string
      to two decimal places
*/
public class WordAvg
{
   public static void main(String[] args)
   {
      Scanner in = new Scanner(System.in);

      int numOfWords = 0;
      int avgLength = 0;

      while (in.hasNext())
      {
         String word = in.next();

         avgLength += word.length();
         numOfWords++;
      }

      // more work here
      System.out.printf("%.2f\n", (float)avgLength / (float)numOfWords);
   }
}