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 C# (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = ReadInt();
            var set = new HashSet<string>();
            for (int i = 0; i < n; i++)
            {
                var lines = ReadLines();
                if (lines[0] == "insert")
                {
                    set.Add(lines[1]);
                }
                else if (lines[0] == "find")
                {
                    if (set.Contains(lines[1]))
                    {
                        Console.WriteLine("yes");
                    }
                    else
                    {
                        Console.WriteLine("no");
                    }
                }
            }
        }

        static string ReadLine()
        {
            return Console.ReadLine();
        }

        static int ReadInt()
        {
            return int.Parse(ReadLine());
        }

        static string[] ReadLines()
        {
            return ReadLine().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries);
        }

        static IEnumerable<int> ReadInts()
        {
            return ReadLines().Select(x => int.Parse(x));
        }
    }

    //static class Console
    //{
    //    static StreamReader reader = new StreamReader("input.txt");

    //    public static string ReadLine()
    //    {
    //        return reader.ReadLine();
    //    }
    //}
}