Friendly Chongchong

Interview

Time limit1sMemory limit1024 MB

Summary

Given N meeting records in order, count how many people are dancing the rainbow dance after the last record, starting from ChongChong alone.

Level: Easy3 of 10
Topics: Hash map, Simulation
Solved: No attempts yet

Problem

Chongchong doing the rainbow dance while another Chongchong watches

Chongchong got a chance to appear at the 2nd Gomgom Cup through his friend Gomgom!

Chongchong wants to win over the audience by showing off his special trick, the rainbow dance. The dance is so addictive that everyone who sees it ends up copying it.

Two Chongchongs doing the rainbow dance

$N$ records of people meeting each other are given in chronological order. (Chongchong is a rabbit, but for this problem, we assume he is a person.)

When a person who is not dancing the rainbow dance meets a person who is dancing it, the first person starts dancing it from the time of the meeting.

Before the records begin, Chongchong is the only one dancing the rainbow dance. Find how many people are dancing the rainbow dance after the last record!

Input

The first line contains the number of records $N\ (1 \le N \le 1\ 000)$ . The next $N$ lines each contain one record. Line $i + 1$ contains the names $A\_i$ and $B\_i$ of the two people in the $i$ -th meeting, separated by a space. $A\_i$ and $B\_i$ are strings of digits and English letters, up to 20 characters long, and they are different from each other.

Chongchong's name is ChongChong, and it appears in the records at least once. No two people share a name, and names are case-sensitive. (ChongChong and chongchong are different names.)

Output

Print the number of people dancing the rainbow dance after the last record.

Examples1

Example 1

Input

12
bnb2011 chansol
chansol chogahui05
chogahui05 jthis
jthis ChongChong
jthis jyheo98
jyheo98 lms0806
lms0806 pichulia
pichulia pjshwa
pjshwa r4pidstart
r4pidstart swoon
swoon tony9402
tony9402 bnb2011

Expected output