import fileinput, re

class Lexer:
    def __init__(self):
        self.tokenPattern = re.compile(r"""FORW|BACK|LEFT|RIGHT|DOWN|UP|COLOR|
                                           REP|\d+|#[\dA-F]{6}|\.|\"|\s+$|%"""
                                           ,re.MULTILINE)
        self.lineNumber = 0

    def __iter__(self):
        return self.__next__()

    def __next__(self):
        for line in fileinput.input():
            line = re.findall(self.tokenPattern, line)
            self.lineNumber += 1
            for token in line:
                yield token