Problem:
Search III

Your task is to write a program of a simple dictionary which implements the following instructions:

insert str: insert a string str in to the dictionary

find str: if the distionary contains str, then print 'yes', otherwise print 'no'

Input

In the first line n, the number of instructions is given. In the following n lines, n instructions are given in the above mentioned format.

Output

Print yes or no for each find instruction in a line.

Constraints

A string consists of 'A', 'C', 'G', or 'T'

1 ≤ length of a string ≤ 12

n ≤ 1000000

Sample Input 1

5
insert A
insert T
insert C
find G
find A

Sample Output 1

no
yes

Sample Input 2

13
insert AAA
insert AAC
insert AGA
insert AGG
insert TTT
find AAA
find CCC
find CCC
insert CCC
find CCC
insert T
find TTT
find T

Sample Output 2

yes
no
no
yes
yes
yes

Notes

Template in C

Solution in JAVA (judge verdict: Accepted)

import java.util.Scanner;
import java.util.HashSet;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        HashSet<String> set = new HashSet<String>();

        String x,y;
        int n = sc.nextInt();
        int i;

        for(i = 0;i < n;i++){
            x = sc.next();
            y = sc.next();

            if(x.equals("insert")){
                set.add(y);
            }

            if(x.equals("find")){
                if(set.contains(y)){
                    System.out.printf("yes\n");
                }else{
                    System.out.printf("no\n");
                }
            }
        }
    }
}