Given an array $a_1$ , $a_2$ , .... $a_n$ and a number p . You need to find how many ordered pairs (x,y) (where x and y are the indices of the array $a_i$ ) exists which sum to p .

$Input :$

The first line of the input consists of a single integer n ( $1 \le n \le 100000$) . The second line of the input consists of array $a_i$ ($-10^8 \le a_i \le 10^8$). The third line of the input consists of number p($-2 \cdot 10^8 \le p \le 2 \cdot 10^8$).

$Output :$

Output should be a single integer representing the number of ordered pair (x,y).