/**
	author:  shobonvip
	created: 2025.08.16 18:04:39
**/

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#include<atcoder/fenwicktree>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef long long ll;

#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()

template <typename T> bool chmin(T &a, const T &b) {
	if (a <= b) return false;
	a = b;
	return true;
}

template <typename T> bool chmax(T &a, const T &b) {
	if (a >= b) return false;
	a = b;
	return true;
}

template <typename T> T max(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
	return ret;
}

template <typename T> T min(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
	return ret;
}

template <typename T> T sum(vector<T> &a){
	T ret = 0;
	for (int i=0; i<(int)a.size(); i++) ret += a[i];
	return ret;
}


int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	
	int n,q;cin>>n>>q;
	string s;cin>>s;
	string org=s;

	vector seg0(26*26*26,atcoder::fenwick_tree<ll>(0));
	vector seg1(26*26*26,atcoder::fenwick_tree<ll>(0));
	vector dat(26*26*26,vector<int>(0));

	auto ston = [&](string s) -> int {
		return int(s[0]-'a')*26*26+int(s[1]-'a')*26+int(s[2]-'a');
	};


	rep(i,2,n){
		dat[ston(s.substr(i-2,3))].push_back(i);
	}

	vector<int> t(q),k(q),l(q),r(q);
	vector<char> c(q);
	vector<string> a(q);
	rep(i,0,q){
		cin>>t[i];
		if(t[i]==1){
			cin>>k[i]>>c[i];k[i]--;
			s[k[i]]=c[i];
			rep(j,max(2,k[i]),min(k[i]+3,n)){
				dat[ston(s.substr(j-2,3))].push_back(j);
			}
		}else{
			cin>>l[i]>>r[i]>>a[i];
			l[i]--;
		}
	}
	s=org;

	rep(i,0,26*26*26){
		sort(all(dat[i]));
		dat[i].erase(unique(all(dat[i])),dat[i].end());
		seg0[i]=atcoder::fenwick_tree<ll>((int)dat[i].size());
		seg1[i]=atcoder::fenwick_tree<ll>((int)dat[i].size());
	}

	
	rep(i,2,n){
		int x = ston(s.substr(i-2,3));
		int idx = int(lower_bound(all(dat[x]),i)-dat[x].begin());
		seg0[x].add(idx,1LL);
		seg1[x].add(idx,(ll)i);
	}

	rep(i,0,q){
		if(t[i]==1){
			rep(j,max(2,k[i]),min(k[i]+3,n)){
				int x = ston(s.substr(j-2,3));
				int idx = int(lower_bound(all(dat[x]),j)-dat[x].begin());
				seg0[x].add(idx,-1LL);
				seg1[x].add(idx,-(ll)j);
			}
			s[k[i]]=c[i];
			rep(j,max(2,k[i]),min(k[i]+3,n)){
				int x = ston(s.substr(j-2,3));
				int idx = int(lower_bound(all(dat[x]),j)-dat[x].begin());
				seg0[x].add(idx,1LL);
				seg1[x].add(idx,(ll)j);
			}
		}else{
			int x=ston(a[i]);
			if(r[i]-l[i]<=2){
				cout<<0<<'\n';
				continue;
			}
			int lb=int(lower_bound(all(dat[x]),l[i]+2)-dat[x].begin());
			int ub=int(lower_bound(all(dat[x]),r[i])-dat[x].begin());
			ll v1=seg1[x].sum(lb,ub);
			ll v0=seg0[x].sum(lb,ub);
			ll ans=v1-(l[i]+1)*v0;
			cout<<ans<<'\n';
		}
	}
}