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'

Notes

Template in C

Constraints

* A string consists of 'A', 'C', 'G', or 'T'
* 1 ≤ length of a string ≤ 12
* n ≤ 1000000

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.

Examples

Input

5
insert A
insert T
insert C
find G
find A


Output

no
yes


Input

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


Output

yes
no
no
yes
yes
yes
import java.io.*;
import java.util.*;
public class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader scan = new BufferedReader (new InputStreamReader(System.in));
        int n = Integer.parseInt(scan.readLine());
        Map<String, String> seq = new HashMap<>();
        for(int x = 0; x < n; x++){
            String check = scan.readLine();
            if(check.startsWith("insert")){
                seq.put(check.substring(7), check.substring(7));
            }
            else{
                if(seq.containsKey(check.substring(5))){
                    System.out.println("yes");
                }
                else{
                    System.out.println("no");
                }
            }
        }
    }
}
