<p>#pragma GCC optimize("O3")<br />#include &lt;bits/stdc++.h&gt;<br />#define _ ios::sync_with_stdio(0),cin.tie(nullptr);</p>
<p>using namespace std;<br />const char* s[2]={"no\n","yes\n"};<br />int main() { _<br /> string ss;<br /> while(cin &gt;&gt; ss) cout &lt;&lt; s[equal(ss.begin(),ss.begin()+ss.size()/2,ss.rbegin())];<br />}</p>