Nenokku#2355
A very famous author of a no less famous book decided to write a sequel to his work. He wrote all his books on a computer connected to the Internet. Because of this carelessness, a boy named Nenokku managed to gain access to the yet-unwritten book. Every evening, the boy would log into the writer's computer and copy new entries onto his own computer. After copying another chapter, Nenokku became interested: did the writer use the word "book" at least once? But he doesn't like reading books (he'd rather browse the Internet), so he asks you to find out whether certain words appear in the text. Of course, he's interested in more than just one word.
Each line of the input contains one of two entries:
? word, where word is a sequence of no more than Latin letters;
A text, where text is a sequence of no more than 10^5 Latin letters.
The first entry means a query to check whether the substring word is present in the work. The second entry means to append the string text to the work.
The writer has only just begun, so the total length of the text does not exceed 10^5 characters. The input file size does not exceed megabytes.
For each query line beginning with ?, print "YES" if the substring word is found, otherwise print "NO". The search must be case-insensitive.
Example 1