Code copying is a major problem on many online programming judges. There are $N$ coders, of which some of them copy code from others. Coder $i$ knows that only coder $a_i$ copied from them.

There are always some "sources" from which coders copy from. A "source" is defined as a coder who does not copy from anyone. Your task is to find out how many "sources" there are.

Input Specification

The first line will contain the integer $N$ $(1\le N\le {10}^6)$, the number of coders there are.

The second line will contain $N$ integers, $a_1,a_2,\dots ,a_N$ $(0\le a_i<i)$. The $i^{th}$ integer means that coder $a_i$ copies from coder $i$. If $a_i=0$, this means no coders copies from coder $i$.

Output Specification

Output the number of "sources".

Constraints

Subtask 1 [20%]

$N\le 1000$

Subtask 2 [80%]

No additional constraints.

Sample Input 1

5
0 1 1 3 2

Sample Output 1

2

Sample Input 2

9
0 1 1 3 4 5 6 4 6

Sample Output 2

4