##############################################
#https://atcoder.jp/contests/abc141/submissions/77328131

from random import randrange

MOD=(1<<61)-1
base=randrange(256,MOD-1)

def rolling_hash(s):
    n=len(s)
    hash_value=[0]*(n+1)
    power=[1]*(n+1)
    for i in range(n):
        power[i+1]=power[i]*base%MOD
        if isinstance(s[i],str):
            value=ord(s[i])+1
        else:
            value=s[i]+1
        hash_value[i+1]=(hash_value[i]*base+value)%MOD
    
    return hash_value,power

def get_hash(hash_value,power,left,right):
    return (hash_value[right]-hash_value[left]*power[right-left])%MOD

##############################################

N,Q=map(int,input().split())
S=list(input())
ans=[]
for _ in range(Q):
    q=list(input().split())
    if q[0]=='1':
        i,c=q[1:]
        i=int(i)-1
        S[i]=c
    else:
        t=q[1]
        h,p=rolling_hash(S)
        M=len(t)
        ht,_=rolling_hash(t)
        ok=False
        tar=ht[M]
        for l in range(N-M+1):
            hash=get_hash(h,p,l,l+M)
            if hash==tar:
                ok=True
                break
        ans.append('Yes' if ok else 'No')

import sys
sys.stdout.write('\n'.join(map(str,ans))+'\n')