QOJ.ac

QOJ

Time Limit: 1 s Memory Limit: 32 MB Total points: 100

#11859. Piggy Banks

الإحصائيات

Byteazar the Dragon has $N$ piggy banks. Each piggy bank can either be opened with its corresponding key or smashed. Byteazar has put the keys in some of the piggy banks - he remembers which key has been placed in which piggy bank. Byteazar intends to buy a car and needs to gain access to all of the piggy banks. However, he wants to destroy as few of them as possible. Help Byteazar to determine how many piggy banks have to be smashed.

Write a programme which:

  • reads from the standard input the number of piggy banks and the deployment of their corresponding keys,
  • finds the minimal number of piggy banks to be smashed in order to gain access to all of them,
  • writes the outcome to the standard output.

Input

The first line of the standard input contains a single integer $N$ ($1 ≤ N ≤ 1\,000\,000$) - this is the number of piggy banks owned by the dragon. The piggy banks (as well as their corresponding keys) are numbered from $1$ to $N$. Next, there are $N$ lines: the $(i+1)$’st line contains a single integer - the number of the piggy bank in which the $i$’th key has been placed.

Output

The first and only line of the standard output should contain a single integer - the minimal number of piggy banks to be smashed in order to gain access to all of the piggy banks.

Example

Input

4
2
1
2
4

Output

2

In the foregoing example piggy banks 1 and 4 have to be smashed.

Discussions

About Discussions

The discussion section is only for posting: Editorials, General Discussions (problem-solving strategies, alternative approaches), and Off-topic conversations.

This is NOT for reporting issues! If you want to report bugs or errors, please use the Issues section below.

Open Discussions 0
No discussions in this category.

Issues

About Issues

If you find any issues with the problem (statement, scoring, time/memory limits, test cases, etc.), you may submit an issue here. A problem moderator will review your issue.

Guidelines:

  1. This is not a place to publish discussions, editorials, or requests to debug your code. Issues are only visible to you and problem moderators.
  2. Do not submit duplicated issues. Submitting multiple issues may cause your account to be banned.
  3. Issues must be filed in English or Chinese only.
Active Issues 0
No issues in this category.
Closed/Resolved Issues 0
No issues in this category.