#  MeanvalueException.py (c) 1997-2006 Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-04-13  File created.
#  2006-05-27  Last modification.


print  "\n This program calculates the mean value of" \
       "\n the integers that you enter from the keyboard." \
       "\n The program stops when you enter a letter. \n"

number_of_integers_given  =  0
sum_of_integers           =  0 

keyboard_input_is_numerical  =  True

while  keyboard_input_is_numerical  ==  True  :

   try :
      print  "   Enter an integer: ",
      integer_from_keyboard  =  int( raw_input() ) 

      number_of_integers_given  +=  1
      sum_of_integers  =  sum_of_integers + integer_from_keyboard

   except :
      keyboard_input_is_numerical  =  False

mean_value  =  0.0

if  number_of_integers_given  >  0 :

    mean_value  =  float( sum_of_integers ) /               \
                   float( number_of_integers_given ) 

print "\n The mean value is: %f"  %  ( mean_value )