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

#define MAX 1000000
#define Length_char 13

int main(void) 
{
	char Dict[MAX][Length_char] = {};
	char cmd[7] = {};
	char obj[Length_char] = {};
	char input[25] = {};
	int max_order = 0;
	int i = 0;
	int j = 0;
	int k = 0;
	int num = 0;
	int flag = 0;
	
	fgets( input, 25, stdin );
	max_order = atoi(input);
	
	for ( i = 0; i < max_order; i++ ) {
		fgets( input, 25, stdin);
		
		for( j = 0; input[j] != ' '; j++ ) {
		}
		input[j] = '\0';
		strcpy(cmd, input);
		
		k = j+1;
		for( ; input[j] != '\r'; j++ ) {
		}
		input[j] = '\0';
		strcpy(obj, &input[k]);
		
		if ( strcmp(cmd, "insert") == 0 ) {
			flag = 0;
			for ( j = 0; j < num; j++ ) {
				if ( strcmp( obj, Dict[j] ) == 0 ) {
					flag = 1;
					break;
				}
			}
			
			if ( flag == 0 ) {
				strcpy( Dict[num], obj );
				//printf("%s\n", Dict[num]);
				num++;
			}
		} else if ( strcmp(cmd, "find" ) == 0) {
			for ( j = 0; j < num; j++ ) {
				flag = 0;
				if ( strcmp( Dict[j], obj ) == 0 ) {
					printf("yes\n");
					flag = 1;
					break;
				} 
			}
			
			if ( flag == 0 ) {
				printf("no\n");
			}
		}
	}
	
	return 0;
}
