Score : $200$ points
Given are a positive integer $N$ and a string $S$ of length $N$ consisting of lowercase English letters.
Determine whether the string is a concatenation of two copies of some string. That is, determine whether there is a string $T$ such that $S = T + T$.
Input is given from Standard Input in the following format:
$N$ $S$
If $S$ is a concatenation of two copies of some string, print Yes; otherwise, print No.
6 abcabc
Yes
Let $T = $ abc, and $S = T + T$.
6 abcadc
No
1 z
No