#include<stdio.h>
#include<string.h>
#define M 1046527
#define NIL -1
#define L 14
char H[M][L];

//?°?????¬??????¬??¢?????°???
int getChar(char ch)
{
	if(ch=='A')return 1;
	else if(ch=='C')return 2;
	else if(ch=='G')return 3;
	else if(ch=='T')return 4;
	else return 0;
}
//?°?????¬??????¬??¢?????°?????¶??????key
long long getKey(char str[])
{
	long long sum=0,p=1,i;
	for(i=0;i<strlen(str);i++)
	{
		sum+=p*(getChar(str[i]));
		p*=5;
	}
	return sum;
}
int h1(int key){return key%M;}
int h2(int key){return 1+(key%(M-1));}
int find(char str[])
{
	long long key,i,h;
	key=getKey(str);	//?°?????¬??????¬??¢?????°???
	for(i=0;;i++){
		h=(h1(key)+i*h2(key))%M;
		if(strcmp(H[h],str)==0)return 1;
		else if(strlen(H[h])==0)return 0;
	}
	return 0;
}
int Insert(char str[])
{
	long long key,i,h;
	key=getKey(str);//?°?????¬??????¬??¢?????°???
	for(i=0;;i++){
		h=(h1(key)+i*h2(key))%M;
		if(strcmp(H[h],str)==0)return 1;
		else if(strlen(H[h])==0){
			strcpy(H[h],str); //???????????°??? ?°±??¨????????¶????????????????´? ???????????????????????????????????????h?§??????\?????? ?°±?????\
			return 0;
		}
	}
}


int main()
{
	int i,n,h;
	char str[L],com[9];
	for(i=0;i<M;i++) H[i][0]='\0';
		scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		scanf("%s %s",com,str);//?????¨????????´???????????\?????°scanf
		if(com[0]=='i')
			Insert(str);
		else
		{
			if(find(str))
				printf("Yes\n");
			else
				printf("no\n");
		}
	}
	return 0;
}