CF1754A Technical Support

### 题面翻译 给定一个只包含大写字母 $\texttt{Q}$ 和 $\texttt{A}$ 的字符串，如果字符串里的每一个 $\texttt{Q}$ 都能与**在其之后**的 $\texttt{A}$ 一一对应地匹配，则输出字符串 $\texttt{Yes}$，否则输出字符串 $\texttt{No}$。注意，可以有 $\texttt{A}$ 没有被匹配，但每个 $\texttt{Q}$ 必须成功地匹配。

输入一个只包含大写字母 $\texttt{Q}$ 和 $\texttt{A}$ 的字符串。

输出字符串 $\texttt{Yes}$ 或 $\texttt{No}$。

In the first test case the two questions from the client are followed with two specialist's answers. So this dialog may correspond to the rules of work. In the second test case one of the first two questions was not answered. In the third test case the technical support manager sent two messaged as the answer to the only message of the client.