Solving this task consists of several steps, and each next step is opened whenever the current step is solved correctly. You always have access to the current and all previous steps data

Your task is to implement a simple container of integer numbers As a

first step, consider implementing the following two operations

ADD should add the specified integer value to the container Returns an empty string

EXISTS should check whether the specific integer value exists in the container. Returns "true" if the value exists "false" otherwise

The container is supposed to be empty at the beginning of execution

Given a list of queries return the list of answers for these queries To pass to the next level you have to pass all tests at this level

Example

For

queries $=[$

$["$ADO$","1"],$

$["$ADO$","2"].$

$["$ADO$","5"].$

$["$ADO$","2"],$

$["$EXISTS$","2"],$

$["$EXISTS$","5"].$

$["$EXISTS$","1]$

$["$EXISTS$","4"].$

$["$EXISTS$","3"],$

$["$EXISTS$","0"]$

the output should be solution $($queries$)-("","","","",$"true", "true", "true", "false", "false", "false"$]$

Explanation

Add $1,2,5,2->[1,2,5,2]$

Numbers $2,5,1$ exist in the container

Numbers $4,3,0$ don't exist in the container

Input$/$Output

$[$execution time limit$]4$ seconds $($java$)$

$($memory limit$)1$ GB

$[$input$)$ array array string queries

An array of queries, guaranteed that all queries consist only of operations described in the description and these operations satisfy the format described in the description All integer's represents as string are from range $[-100,100]$