Description
Give you a string (S) with a length of (n) and only lowercase letters (subscripts start from (1) to (n)), perform the following two operations (Q) times:
1 i c: Replace the character at position (i) in the string (S) with the character (c);
2 l r: The number of different characters from the (l)th position to the (r)th position in the query string (S).
Format
Input
The first line contains an integer (n), which represents the length of the string (S).
The second line contains a string (S) of length (n), containing only lowercase letters.
The third line contains an integer (Q), which represents the number of operations.
In line (4 sim Q+3), each line describes one of the above two operations.
Output
For each operation (2), the output line contains an integer, which represents the number of different characters in (S[l dots r]).
Sample
Input
7
abcdbbd
6
2 3 6
1 5 z
2 1 1
1 4 a
1 7 d
2 1 7
Output
3
1
5
Hint
( ext{Subtask1(50%)})：(1le n le 100)；
( ext{Subtask2(50%)})：(1le n le 500000, 1 le Q le 20000)。
Sample Code
Code is not available!