#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")

#include <iostream>

#ifdef NyaanLocal
#include "misc/timer.hpp"
#endif
using namespace std;

int N, Q;
char S[200200], a[4];

long long query(int l, int r) {
  int x = a[0] + (a[1] << 8) + (a[2] << 16);
  long long ans = 0, bns = 0, cns = 0, dns = 0, ens = 0, fns = 0, gns = 0,
            hns = 0;

#define f(i) S[i] + (S[i + 1] << 8) + (S[i + 2] << 16)

  int i = 0;
  for (; i + 10 < r; i += 4) {
    bool cond0 = x == f(i + 0);
    bool cond1 = x == f(i + 1);
    bool cond2 = x == f(i + 2);
    bool cond3 = x == f(i + 3);
    ans += cond0 ? i : 0;
    bns += cond0 ? 1 : 0;
    cns += cond1 ? i + 1 : 0;
    dns += cond1 ? 1 : 0;
    ens += cond2 ? i + 2 : 0;
    fns += cond2 ? 1 : 0;
    gns += cond3 ? i + 3 : 0;
    hns += cond3 ? 1 : 0;
  }
  for (; i + 2 < r; i++) {
    bool cond = x == f(i);
    ans += cond ? i : 0;
    bns += cond ? 1 : 0;
  }
  return (ans + cns + ens + gns) - (bns + dns + fns + hns) * (l - 1);
}

int main() {
#ifdef NyaanLocal
  Timer timer;
#endif
  cin >> N >> Q >> S;
  while (Q--) {
    int cmd;
    cin >> cmd;
    if (cmd == 1) {
      int k;
      char x;
      cin >> k >> x;
      k--;
      S[k] = x;
    } else {
      int l, r;
      cin >> l >> r >> a;
      --l;
      cout << query(l, r) << "\n";
    }
  }
#ifdef NyaanLocal
  cerr << timer() << endl;
#endif
}