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

-----Sample Output-----
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.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "import sys\ninput = sys.stdin.readline\n\ndef solve():\n    ordA = ord('a')\n\n    N = int(input())\n    Ss = input().rstrip()\n    Q = int(input())\n    querys = [tuple(input().split()) for _ in range(Q)]\n\n    idEle = 0\n    def _binOpe(x, y):\n        return x | y\n    def makeSegTree(numEle):\n        numPow2 = 2 ** (numEle-1).bit_length()\n        data = [idEle] * (2*numPow2)\n        return data, numPow2\n    def setInit(As):\n        for iST, A in enumerate(As, numPow2):\n            data[iST] = A\n        for iST in reversed(list(range(1, numPow2))):\n            data[iST] = _binOpe(data[2*iST], data[2*iST+1])\n    def _update1(iA, A):\n        iST = iA + numPow2\n        data[iST] = A\n    def update(iA, A):\n        _update1(iA, A)\n        iST = iA + numPow2\n        while iST > 1:\n            iST >>= 1\n            data[iST] = _binOpe(data[2*iST], data[2*iST+1])\n    def getValue(iSt, iEn):\n        L = iSt + numPow2\n        R = iEn + numPow2\n        ans = idEle\n        while L < R:\n            if L & 1:\n                ans = _binOpe(ans, data[L])\n                L += 1\n            if R & 1:\n                R -= 1\n                ans = _binOpe(ans, data[R])\n            L >>= 1\n            R >>= 1\n        return ans\n\n    data, numPow2 = makeSegTree(N)\n    As = [(1<<(ord(S)-ordA)) for S in Ss]\n    setInit(As)\n\n    anss = []\n    for tp, *vs in querys:\n        if tp == '1':\n            i, c = vs\n            i = int(i)\n            update(i-1, 1<<(ord(c)-ordA))\n        else:\n            L, R = vs\n            L, R = int(L), int(R)\n            v = getValue(L-1, R)\n            anss.append(bin(v).count('1'))\n\n    print(('\\n'.join(map(str, anss))))\n\n\nsolve()\n"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 14475