#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;

using isize = size_t;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
using f64 = long double;
using p2 = pair<i64, i64>;
using el = tuple<i64, i64, i64>;
using mint = atcoder::modint998244353;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  _main();
}

i64 pow(i64 x, i64 n) {
  i64 res = 1;
  i64 t = x;
  while (n > 0) {
    if (n & 1) {
      res = res * t;
    }
    t = t * t;
    n >>= 1;
  }
  return res;
}
i64 pow(i64 x, i64 n, i64 m) {
  i64 res = 1;
  i64 t = x % m;
  while (n > 0) {
    if (n & 1) {
      res = res * t % m;
    }
    t = t * t % m;
    n >>= 1;
  }
  return res;
}

void _main() {
  i64 n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  vector<tuple<i64, i64, i64, string>> query(q);
  map<string, vector<i64>> idx;
  string ss = s;
  for (i64 i = 0; i + 2 < n; i++) {
    string t = ss.substr(i, 3);
    idx[t].push_back(i);
  }
  for (i64 i = 0; i < q; i++) {
    i64 op;
    cin >> op;
    if (op == 1) {
      i64 k;
      char x;
      cin >> k >> x;
      k--;
      query[i] = {op, k, x, ""};
      ss[k] = x;
      for (i64 j = k - 2; j <= k; j++) {
        if (j < 0 || j + 2 >= n) continue;
        string t = ss.substr(j, 3);
        idx[t].push_back(j);
      }
    } else {
      i64 l, r;
      string a;
      cin >> l >> r >> a;
      l--;
      query[i] = {op, l, r, a};
    }
  }
  map<string, atcoder::fenwick_tree<i64>> cnt;
  map<string, atcoder::fenwick_tree<i64>> sum;
  {
    map<string, vector<i64>> nidx;
    for (auto [s, v] : idx) {
      sort(v.begin(), v.end());
      v.erase(unique(v.begin(), v.end()), v.end());
      nidx[s] = v;
      cnt[s] = atcoder::fenwick_tree<i64>(v.size());
      sum[s] = atcoder::fenwick_tree<i64>(v.size());
    }
    swap(nidx, idx);
  }
  for (i64 i = 0; i + 2 < n; i++) {
    string t = s.substr(i, 3);
    i64 j = lower_bound(idx[t].begin(), idx[t].end(), i) - idx[t].begin();
    assert(idx[t][j] == i);
    cnt[t].add(j, 1);
    sum[t].add(j, i);
  }
  for (auto [op, a, b, S] : query) {
    if (op == 1) {
      for (i64 j = a - 2; j <= a; j++) {
        if (j < 0 || j + 2 >= n) continue;
        string t = s.substr(j, 3);
        i64 k = lower_bound(idx[t].begin(), idx[t].end(), j) - idx[t].begin();
        assert(idx[t][k] == j);
        cnt[t].add(k, -1);
        sum[t].add(k, -j);
      }
      s[a] = b;
      for (i64 j = a - 2; j <= a; j++) {
        if (j < 0 || j + 2 >= n) continue;
        string t = s.substr(j, 3);
        i64 k = lower_bound(idx[t].begin(), idx[t].end(), j) - idx[t].begin();
        cnt[t].add(k, 1);
        sum[t].add(k, j);
      }
    } else {
      if (a + 3 > b) {
        cout << "0\n";
        continue;
      }
      i64 l = lower_bound(idx[S].begin(), idx[S].end(), a) - idx[S].begin();
      i64 r = lower_bound(idx[S].begin(), idx[S].end(), b - 2) - idx[S].begin();
      i64 s = sum[S].sum(l, r);
      i64 c = cnt[S].sum(l, r);
      cout << s + c - c * a << "\n";
    }
  }
}