Process Queries on a String

You are given an initial string s of length \(n\) and a sequence of \(q\) queries. There are two types of queries:

• Type 1: 1 i c — Replace the character at position \(i\) in the string with the character \(c\).
• Type 2: 2 l r — Count the number of distinct characters in the substring from position \(l\) to \(r\) (inclusive) and print the result.

For each query of type 2, output the answer on a new line. Note that the positions are 1-indexed.

inputFormat

The input is read from standard input (stdin) and has the following format:

The first line contains two integers (n) and (q) — the length of the string and the number of queries.

The second line contains the string s.

The next (q) lines each contain a query in one of the two formats:

• 1 i c — Update the character at position \(i\) to \(c\).
• 2 l r — Query the number of distinct characters between positions \(l\) and \(r\) (inclusive).

outputFormat

For each query of type 2, output a single integer on a new line representing the number of distinct characters in the specified substring.## sample

11 5
abracadabra
2 1 3
1 4 z
2 1 3
2 1 4
1 10 y

3
3
4