The Levenshtein edit distance between two strings is the minimum possible number of insertions, deletions, or substitutions to convert one word into another word. In this case, each insertion, deletion and substitution has a cost of 1.
For example, the distance between
rollingis 3, because deletions cost 1, and we need to delete 3 characters. The distance between
tallis 1, because substitutions cost 1.
Your task is to calculate the Levenshtein edit difference between an input string and your source. This is tagged quine, so cheating quines (for example, reading your source code) are not allowed.
The input will be non-empty and will be composed of ASCII, unless your source contains non-ASCII, in which case the input may include Unicode. Regardless, the Levenshtein distance will be measured in characters, not bytes.
The output is the minimum Levenshtein edit distance of the input and your source.
This is code-golf, so shortest answer, in bytes, wins.