ABC Conjecture

You are given two strings $A$ and $B$, both of length $N$ and containing only the characters `a`, `b`, and `c`. In one move, you can modify string $A$ as follows: - Choose three indices $i, j, k$ ($1 \leq i \lt j \lt k \leq N$) such that $A_i = \texttt{a}, A_j = \texttt{b}, A_k = \texttt{c}$. That is, choose some [subsequence](https://en.wikipedia.org/wiki/Subsequence) of $A$ that is `abc`. -