Replace With First

You are given two strings, $S$ and $T$, of lengths $N$ and $M$ respectively. You can perform the following operation on **any** of the strings: - Replace a substring with its first character. (i.e. “ab**cab**c” -> “ab**c**c”) What is the minimum number of operations to make both of the strings equal? Or determine that it is impossible to make both of the strings equal. ### Input - The first li