import java.io.*;

class Average7
{
// A program that calculates the average of a series of integers. 
// A sentinel value is used to indicate the end of the series.
// The program is intended to be used with input redirected from a
// file, so it does not prompt for input.
  
 static final int SENTINEL = -999;

 public static void main(String[] args) throws IOException
 {
  BufferedReader in = Text.open(System.in);
  int sum=0,count=1,n;
  while(true)
     {
      n=Text.readInt(in);
      if(n==SENTINEL)
         break;
      sum+=n;
      count++;
     }
  System.out.println("Average is: "+Text.writeDouble((double)sum/(count-1),5,3));
 }
}