#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; }
template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; }
const std::vector<std::pair<int, int>> grid_dxs{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <class T1, class T2> T1 floor_div(T1 num, T2 den) { return (num > 0 ? num / den : -((-num + den - 1) / den)); }
template <class T1, class T2> std::pair<T1, T2> operator+(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first + r.first, l.second + r.second); }
template <class T1, class T2> std::pair<T1, T2> operator-(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first - r.first, l.second - r.second); }
template <class T> std::vector<T> sort_unique(std::vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <class T> int arglb(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); }
template <class T> int argub(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); }
template <class IStream, class T> IStream &operator>>(IStream &is, std::vector<T> &vec) { for (auto &v : vec) is >> v; return is; }

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec);
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr);
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const pair<T, U> &pa);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa);
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp);
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp);
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl);

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; }
template <class... T> std::istream &operator>>(std::istream &is, std::tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; }
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa) { return os << '(' << pa.first << ',' << pa.second << ')'; }
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m";
#define dbg(x) std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl
#define dbgif(cond, x) ((cond) ? std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl : std::cerr)
#else
#define dbg(x) ((void)0)
#define dbgif(cond, x) ((void)0)
#endif

// 0-indexed BIT (binary indexed tree / Fenwick tree) (i : [0, len))
template <class T> struct BIT {
    int n;
    std::vector<T> data;
    BIT(int len = 0) : n(len), data(len) {}
    void reset() { std::fill(data.begin(), data.end(), T(0)); }
    void add(int pos, T v) { // a[pos] += v
        pos++;
        while (pos > 0 and pos <= n) data[pos - 1] += v, pos += pos & -pos;
    }
    T sum(int k) const { // a[0] + ... + a[k - 1]
        T res = 0;
        while (k > 0) res += data[k - 1], k -= k & -k;
        return res;
    }

    T sum(int l, int r) const { return sum(r) - sum(l); } // a[l] + ... + a[r - 1]

    template <class OStream> friend OStream &operator<<(OStream &os, const BIT &bit) {
        T prv = 0;
        os << '[';
        for (int i = 1; i <= bit.n; i++) {
            T now = bit.sum(i);
            os << now - prv << ',', prv = now;
        }
        return os << ']';
    }
};

constexpr int D = 26;

int Encode(const string &s3) {
    assert(s3.size() == 3);
    int a = s3[0] - 'a';
    int b = s3[1] - 'a';
    int c = s3[2] - 'a';
    return a * D * D + b * D + c;
}

int main() {
    int N, Q;
    string S;
    cin >> N >> Q >> S;

    vector<tuple<int, int, int, string>> queries(Q);
    for (auto &[tp, l, r, a] : queries) {
        cin >> tp;
        if (tp == 1) {
            cin >> l >> a;
            --l;
            r = -1;
        } else if (tp == 2) {
            cin >> l >> r >> a;
            --l;
        } else {
            assert(false);
        }
    }
    dbg(queries);

    array<vector<int>, D * D * D> w2is;
    REP(i, N - 2) w2is[Encode(S.substr(i, 3))].push_back(i);

    {
        auto T = S;
        for (auto [tp, l, r, a] : queries) {
            if (tp == 1) {
                T[l] = a[0];
                FOR(i, l - 2, l + 1) {
                    if (i >= 0 and i + 2 < N) w2is[Encode(T.substr(i, 3))].push_back(i);
                }
            }
        }
    }
    for (auto &is : w2is) is = sort_unique(is);

    array<BIT<int>, D * D * D> bit0;
    array<BIT<lint>, D * D * D> bit1;
    REP(d, D * D * D) {
        bit0[d] = BIT<int>(w2is[d].size());
        bit1[d] = BIT<lint>(w2is[d].size());
    }

    REP(i, N - 2) {
        const auto e = Encode(S.substr(i, 3));
        const int pos = arglb(w2is[e], i);
        bit0[e].add(pos, 1);
        bit1[e].add(pos, i);
    }

    {
        for (auto [tp, l, r, a] : queries) {
            if (tp == 1) {
                FOR(i, l - 2, l + 1) {
                    if (i >= 0 and i + 2 < N) {
                        const int e = Encode(S.substr(i, 3));
                        const int pos = arglb(w2is[e], i);
                        bit0[e].add(pos, -1);
                        bit1[e].add(pos, -i);
                    }
                }
                S[l] = a[0];
                FOR(i, l - 2, l + 1) {
                    if (i >= 0 and i + 2 < N) {
                        const int e = Encode(S.substr(i, 3));
                        const int pos = arglb(w2is[e], i);
                        bit0[e].add(pos, +1);
                        bit1[e].add(pos, +i);
                    }
                }
            } else {
                const int e = Encode(a);
                const int il = arglb(w2is[e], l);
                const int ir = arglb(w2is[e], r - 2);

                lint prod0 = bit0[e].sum(il, ir);
                auto prod1 = bit1[e].sum(il, ir);
                cout << prod1 - prod0 * (l - 1) << '\n';
            }
        }
    }
}