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 Python3 (judge verdict: Time Limit Exceeded)

n = int(input())
c = [0]*n
st = []

for i in range(n):
    c[i] = list(input().split())
    if c[i][0]=='insert':
        st.append(c[i][1])
    if c[i][0]=='find':
        flag = 0
        for j in range(len(st)):
            if c[i][1]==st[j]:
                flag = 1
        if flag == 0:
            print("no")
        else:
            print("yes")