#include <stdio.h>
#include <string.h>

#define N 1000000
#define M 12
#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;
}
int getKey(char str[]){
  int sum = 0, p = 1, i;
  for ( i = 0; i < strlen(str); i++ ){
    sum += p*(getChar(str[i]));
    p *= 5;
  }
  return sum;
}


int main(){
  int i, j, n, h=0, k=0, flag=1, m=0;
  char str[L], com[9];
  scanf("%d",&n);
  for(i = 0; i < n; i++){
    scanf("%s%s",com,str);
    if(com[0] == 'i'){
      k = getKey(str);
      while(1){
	if(H[m] == NULL) break;
	  h = (k%M + m*(1+k%(M-1)))%M;
	  m++;
      }
      strcpy(H[h], str);
      m=0;
    }
    else{
      for(j = 0; j < M; j++){
	if(strcmp(str,H[j]) == 0){
	  flag = 0;
	  break;
	}
	if(flag == 0) printf("yes\n");
	else{
	  printf("no\n");
	  flag = 1;
	  }
      }
    } 
  }
  return 0;
}