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
#include<iostream>
#include<set>
#include<string>

using namespace std;

int main(){
	set<string> S;
	string command,key;
	int n;
	cin>>n;
	for(int i=0;i<n;++i){
		cin>>command;
		if(command=="insert"){
			cin >> key;
			S.insert(key);
		}
		else if(command == "find"){
			cin >> key;
			if(S.count(key) == 1){
			    cout << "yes" << endl;
			}
			else{
			    cout << "no" << endl;
			}
		}
	}
}

