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 Go (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var s = bufio.NewScanner(os.Stdin)
var w = bufio.NewWriter(os.Stdout)

func main() {
	s.Split(bufio.ScanWords)

	s.Scan()
	n, _ := strconv.Atoi(s.Text())

	T := make(map[string]int)
	for i := 0; s.Scan() && i < n; i++ {
		cmd := s.Text()
		if cmd[0] == 'f' {
			s.Scan()
			if _, ok := T[s.Text()]; ok {
				fmt.Fprintln(w, "yes")
				continue
			}
			fmt.Fprintln(w, "no")
			continue
		}
		s.Scan()
		T[s.Text()] = 0
	}

	w.Flush()
}