def isOnlyDigits(num):
# Returns True if num is a string made up only of digits. Otherwise returns False.
  if num == " ":
    return False

  #for i in num:
      #print i
  #if i  in ["0","1","2","3","4","5","6","7","8","9"]:
     # return True


print  isOnlyDigits("326ff")


