#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define all(s) (s).begin(), (s).end()
#define rall(s) (s).rbegin(), (s).rend()
#define rep(i,l,r) for(int i=l;i<r;i++)
#define rrep(i,r,l) for(int i=r;i>=l;i--)

using ll=long long;
using vi=vector<int>;
using vvi=vector<vector<int>>;
using vs=vector<string>;
using vc=vector<char>;
using vvc=vector<vc>;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using vb=vector<bool>;
using vvb=vector<vb>;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
using vpii=vector<pii>;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int N,Q;cin>>N>>Q;
	string S;cin>>S;
	for(;Q--;)
	{
		int t;cin>>t;
		if(t==1){
			int i;
			char c;
			cin>>i>>c;i--;
			S[i]=c;
		}
		else{
			string t;cin>>t;
			if(S.find(t)!=string::npos)cout<<"Yes"<<'\n';
			else cout<<"No"<<'\n';
		}
	}
}