Problem:
Score : 500 points

Problem Statement

You are given a string S of length N consisting of lowercase English letters.

Process Q queries of the following two types:

Type 1: change the i_q-th character of S to c_q. (Do nothing if the i_q-th character is already c_q.)

Type 2: answer the number of different characters occurring in the substring of S between the l_q-th and r_q-th characters (inclusive).

Constraints

N, Q, i_q, l_q, and r_q are integers.

S is a string consisting of lowercase English letters.

c_q is a lowercase English letter.

1 \leq N \leq 500000

1 \leq Q \leq 20000

|S| = N

1 \leq i_q \leq N

1 \leq l_q \leq r_q \leq N

There is at least one query of type 2 in each testcase.

Input

Input is given from Standard Input in the following format:

N
S
Q
Query_1
\vdots
Query_Q

Here, Query_i in the 4-th through (Q+3)-th lines is one of the following:

1 i_q c_q

2 l_q r_q

Output

For each query of type 2, print a line containing the answer.

Sample Input 1

7
abcdbbd
6
2 3 6
1 5 z
2 1 1
1 4 a
1 7 d
2 1 7

Sample Output 1

3
1
5

In the first query, cdbb contains three kinds of letters: b , c , and d, so we print 3.

In the second query, S is modified to abcdzbd.

In the third query, a contains one kind of letter: a, so we print 1.

In the fourth query, S is modified to abcazbd.

In the fifth query, S does not change and is still abcazbd.

In the sixth query, abcazbd contains five kinds of letters: a, b, c, d, and z, so we print 5.

Solution in PyPy3 (2.4.0) (judge verdict: Wrong Answer)

import sys
from copy import copy, deepcopy
input = sys.stdin.readline
'''
n, m = map(int, input().split())
n = int(input())
A = list(map(int, input().split()))
S = input().strip()
for CASES in range(int(input())):
'''
inf = 100000000000000000  # 1e17
mod = 998244353

'''
# example input


'''


def replace(pos, char):
    x = pos
    old_char = A[x]
    while x <= n:
        tr[x][old_char] = 0
        x += x & (-x)
    x = pos
    while x <= n:
        tr[x][char] = 1
        x += x & (-x)
    A[pos] = char


def query(pos, char):
    x = pos
    sum = 0
    while x != 0:
        sum += tr[x][char]
        x -= x & (-x)
    return sum


n = int(input())
S = input().strip()
A = [27] * (n + 1)
'''
for i in range(len(S)):
    A.append(ord(S[i])-ord('a'))
'''
tr = [[0] * 30 for i in range(len(S) + 10)]
for i in range(len(S)):
    replace(i + 1, ord(S[i]) - ord('a'))
q = int(input())
for i in range(q):
    QUERY = list((input().split()))
    if int(QUERY[0]) == 1:
        replace(int(QUERY[1]), ord(QUERY[2]) - ord('a'))
    else:
        sum = 0
        for char in range(ord('a'), ord('z') + 1):
            sum += query(int(QUERY[2]), char - ord('a'))
            sum -= query(int(QUERY[1]) - 1, char - ord('a'))
        print(sum)