输入是命令序列。该命令关键字后退，前进，参观，并退出全部大写。网址没有空格和最多有70个字符。你可以假设没有问题实例需要在任何时间在每个堆叠多于100个元素。输入端的QUIT命令指示。

对于每个命令不是退出等，在执行命令后，如果不忽略该命令打印当前页面的URL。否则，打印“忽略”。每个命令的输出应印上自己的路线。无输出产生的quit命令。-Input is a sequence of commands. The command keywords BACK, FORWARD, VISIT, and QUIT are all in uppercase. URLs have no whitespace and have at most 70 characters. You may assume that no problem instance requires more than 100 elements in each stack at any time. The end of input is indicated by the QUIT command.

For each command other than QUIT, print the URL of the current page after the command is　d if the command is not ignored. Otherwise, print　Ignored . The output for each command should be printed on its own line. No output is produced for the QUIT command.