P Equal To NP

You are given a string $S$, each character of which is either $\verb+N+$ or $\verb+P+$. In one move, you can perform the following operation: - Pick an index $1 \leq i \leq |S|$ and flip $S_i$, i.e, if $S_i = \verb+N+$ set it to $\verb+P+$ and vice versa. Find the minimum number of moves required to obtain a string such that there exists a way to split it into several continuous substrings, each