def check_uva_userid1(what): chars = list(what.lower()) # check first character (must be a letter) if len(chars) == 0: return False if not chars[0].isalpha(): return False chars.pop(0) # check second character (must be a letter) if len(chars) == 0: return False if not chars[0].isalpha(): return False chars.pop(0) # return true if of the form ll if len(chars) == 0: return True # check optional 3rd letter if chars[0].isalpha(): chars.pop(0) # return true if of the form lll if len(chars) == 0: return True # check digit if len(chars) == 0: return False if not chars[0].isdigit(): return False chars.pop(0) # check first letter after the digit if len(chars) == 0: return False if not chars[0].isalpha(): return False chars.pop(0) # return true if of the form lldl or llldl if len(chars) == 0: return True # check second letter after the digit if not chars[0].isalpha(): return False chars.pop(0) # return true if of the form lldll or llldll if len(chars) == 0: return True # check third letter after the digit if not chars[0].isalpha(): return False chars.pop(0) # return true if of the form lldlll or llldlll if len(chars) == 0: return True # if there is more input, then it's not a valid userid return False print(check_uva_userid1(input()))