import java.io.*;

class Average6b
{
// A program that calculates the average of a series of 
// integers. It prompts for each one. A sentinel value is 
// used to indicate the end of the series.
// Catches invalid input
  
 static final int SENTINEL = -999;

 public static void main(String[] args) throws IOException
 {
  BufferedReader in = new BufferedReader
                       (new InputStreamReader(System.in));
  int sum=0,count=1,n,fraction;
  while(true)
     {
      System.out.print("Enter number "+count);
      System.out.print(" (or "+SENTINEL+" to finish): ");
      try {
           n=Integer.parseInt(in.readLine());
           if(n==SENTINEL)
              break;
           sum+=n;
           count++;
          }
      catch(NumberFormatException e)
          {
           System.out.println("Not a valid number");
          }
     }
  System.out.print("Average is: "+sum/(count-1)+".");
  fraction = (sum*100/(count-1))%100;
  if(fraction<10)
     System.out.println("0"+fraction);
  else
     System.out.println(fraction);
 }
}