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 "bits/stdc++.h"
using namespace std;

#define ul unsigned long long
#define ll long long

int main()
{
  ll n;
  string os,ks;
  cin>>n;
  map<string,int> m;
  
  for (ll i = 0; i < n; i++)
  {
    cin>>os;
    cin>>ks;
    if (os=="insert") {
      m[ks]=1;
    }
    else if (os== "find")
    {
      if (m[ks]) cout<<"yes"<<endl;
      else cout<<"no"<<endl;
    }
  }
  

  return 0;
}

