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

using ll = long long;

int main() {
	int N, Q;
	cin >> N >> Q;
	string S;
	cin >> S;
	
	vector<ll> A(N);
	for(int i = 0; i < N; ++i) A[i] = S[i] - 'a' + 1;
	
	vector B(8, vector<ll>(N, 0));
	B[0] = A;
	for(int i = 1; i < 8; ++i) for(int j = 0; j < N - i; ++j) B[i][j] = B[i - 1][j] << 5 | A[j + i];
	
	unordered_map<ll, int> cnt;
	for(int i = 0; i < 8; ++i) for(int j = 0; j < N; ++j) cnt[B[i][j]] += 1;
	
	while(Q--) {
		int cmd;
		cin >> cmd;
		
		if(cmd == 1) {
			int k; char c;
			cin >> k >> c, --k;
			B[0][k] = A[k] = c - 'a' + 1;
			
			for(int i = 1; i < 8; ++i) for(int j = max(0, k - i); j <= k; ++j) if(j + i < N) {
				cnt[B[i][j]] -= 1;
				B[i][j] = B[i - 1][j] << 5 | A[j + i];
				cnt[B[i][j]] += 1;
			}
		}
		
		if(cmd == 2) {
			string T;
			cin >> T;
			
			ll v = 0;
			for(auto c : T) v = (v << 5) + (c - 'a' + 1);
			
			cout << (cnt[v] > 0 ? "Yes" : "No") << "\n";
		}
	}
}