from sortedcontainers import SortedList

class IndexedSet:
    """SortedList + prefix sum 用に拡張"""
    def __init__(self):
        self.sl = SortedList()
        self.sums = []

    def _recalc(self):
        # prefix sum を更新
        self.sums = []
        total = 0
        for v in self.sl:
            total += v
            self.sums.append(total)

    def add(self, x):
        self.sl.add(x)
        self._recalc()

    def remove(self, x):
        self.sl.remove(x)
        self._recalc()

    def lower_bound(self, x):
        return self.sl.bisect_left(x)

    def prefix_sum(self, r):
        if r == 0:
            return 0
        if r > len(self.sums):
            return self.sums[-1]
        return self.sums[r-1]

def encode(s, i):
    return (ord(s[i]) - ord('a')) * 26 * 26 + (ord(s[i+1]) - ord('a')) * 26 + (ord(s[i+2]) - ord('a'))

def solve():
    import sys
    input = sys.stdin.readline

    N, Q = map(int, input().split())
    S = input().strip()
    state = list(S)

    indices = [None] * (26*26*26)
    for i in range(N-2):
        code = encode(S, i)
        if indices[code] is None:
            indices[code] = IndexedSet()
        indices[code].add(i+1)

    for _ in range(Q):
        tmp = input().split()
        q = int(tmp[0])
        if q == 1:
            k = int(tmp[1]) - 1
            x = tmp[2]
            for j in range(k-2, k+1):
                if 0 <= j < N-2:
                    c = encode(state, j)
                    indices[c].remove(j+1)
            state[k] = x
            for j in range(k-2, k+1):
                if 0 <= j < N-2:
                    c = encode(state, j)
                    if indices[c] is None:
                        indices[c] = IndexedSet()
                    indices[c].add(j+1)
        else:
            l = int(tmp[1])
            r = int(tmp[2])
            a = tmp[3]
            code = encode(a, 0)
            if indices[code] is None:
                print(0)
            else:
                p = indices[code].lower_bound(r)
                s = indices[code].lower_bound(l)
                ans = indices[code].prefix_sum(p) - indices[code].prefix_sum(s)
                ans -= (p - s) * (l - 1)
                print(ans)