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

template<typename T>
vector<int> Zalgo(const vector<T> &s){
    int l1 = 0,N = s.size();
    vector<int> ret(N);
    for(int i=1; i<N; i++){
        int l2 = i-l1;
        if(i+ret.at(l2) < l1+ret.at(l1)) ret.at(i) = ret.at(l2);
        else{
            int len = max(0,l1+ret.at(l1)-i);
            while(i+len < N && s.at(len) == s.at(i+len)) len++;
            ret.at(i) = len; l1 = i;
        }
    }
    ret.at(0) = N;
    return ret;
}
vector<int> Zalgo(const string &s){
    int l1 = 0,N = s.size();
    vector<int> ret(N);
    for(int i=1; i<N; i++){
        int l2 = i-l1;
        if(i+ret.at(l2) < l1+ret.at(l1)) ret.at(i) = ret.at(l2);
        else{
            int len = max(0,l1+ret.at(l1)-i);
            while(i+len < N && s.at(len) == s.at(i+len)) len++;
            ret.at(i) = len; l1 = i;
        }
    }
    ret.at(0) = N;
    return ret;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int N,Q; cin >> N >> Q;
    string s; cin >> s;
    while(Q--){
        int type; cin >> type;
        if(type == 1){
            int pos; char c; cin >> pos >> c,pos--;
            s.at(pos) = c;
        }
        else{
            string t; cin >> t;
            auto Z = Zalgo(t+'-'+s);
            bool yes = false;
            for(int i=1; i<Z.size(); i++) yes |= Z.at(i)==t.size();
            cout << (yes?"Yes\n":"No\n");
        }
    }
}