Minimum Segments

You are given a string $S$ of length $N$ consisting of lowercase latin alphabets from $a$ to $t$. A string is called *good* if the frequency of **all** of the characters present in the string is **odd**. For example, $aaba$ is *good* as there are two characters $a$ and $b$ in the string with frequency $3$ and $1$ respectively, both of which are odd. The string $bcb$ is not *good* as the frequency