A plant — Eolymp

Input

The first line contains one integer $n$ ( $1 \leq n \leq 2 \cdot 1 0^{5}$ 1 \leq n \leq 2 \cdot 10^5) — the size of array $a$ .

The second line contains $n$ integers $a_{i}$ a_i ( $- n \leq a_{i} \leq n$ -n \leq a_i \leq n) representing the elements of the array $a$ .

Output

Output the number of pairs $i, j (1 \leq i < j \leq n)$ i,j(1 \le i < j \le n) such that $(a_{i} + a_{j})^{2} = a_{i} + a_{j}$ (a_i+a_j)^2 = a_i + a_j.

Examples

Example 1

Loading

Example 2

Loading

Scoring

( $3$ points): $a_{i} = 0$ a_i = 0
( $3$ points): $0 \leq a_{i} \leq 1$ 0 \le a_i \le 1;
( $3$ points): $- 1 \leq a_{i} \leq 1$ -1 \le a_i \le 1;
( $9$ points): $n \leq 100$ n \le 100;
( $32$ points): no additional constraints