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 JavaScript (judge verdict: Wrong Answer)

process.stdin.resume();
process.stdin.setEncoding('utf8');
 
process.stdin.on('data', function (chunk) {
    var xs = chunk.toString().trim().split('\n').slice(1).map(function(x){ return x.split(' '); });
    var ys = {};
    xs.forEach(function(x){
        if(x[0] === 'insert'){
            ys[x[1]] = true;
        }else if(x[0] === 'find'){
            console.log(ys.hasOwnProperty(x[1]) ? 'yes' : 'no');
        }
    });
});