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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = ip(br);
        Set<String> list=new HashSet<>();
        for(int i=0;i<n;i++){
            String[] lines=br.readLine().split(" ");
            if(lines[0].equals("insert")){
                list.add(lines[1]);
            }else{
                if(list.contains(lines[1])){
                    System.out.println("yes");
                }else{
                    System.out.println("no");
                }
            }
        }
    }

    static boolean isNumber(String num) {
        return Pattern.compile("^\\-?[0-9]*\\.?[0-9]+$").matcher(num).find();
    }

    static int[] createListInt(BufferedReader br) throws IOException {
        String[] lines = br.readLine().split(" ");
        int n = lines.length;
        int[] list = new int[n];
        while (n-- > 0) {
            list[n] = Integer.parseInt(lines[n]);
        }
        return list;
    }

    static int ip(BufferedReader s) throws IOException {
        return Integer.parseInt(s.readLine());
    }
}