Məsələlər
XML
XML
In this problem, you are asked to determine if a given document satisfies the syntax of an XML-like language.
A simple XML-like document can be parsed as a sequence of the following:
\includegraphics{https://static.e-olymp.com/content/e4/e4766b751dea08f51ad48d3d5ae0ca4703f66bfd.jpg}
By the time the entire document is parsed, the context stack is empty for a valid document. We should also note that the empty string is considered valid.
\InputFile
You will be given a number of documents to process. Each document is given as one line oftext which may be empty. The input is terminated by the end of file.
\OutputFile
For each document given, print valid on a single line if it is a valid XML-like document,or invalid otherwise.
Giriş verilənləri #1
the quick brown fox. the <i><b>quick</b> brown</i> fox. <doc>fox & socks.</doc> 3x+5>7 Null: &x00; <doc>the quick brown fox. the <i>quick <b>brown</i></b> fox fox & socks. 3x+5>7 Null: &x0;
Çıxış verilənləri #1
valid valid valid valid valid invalid invalid invalid invalid invalid