SUMX

A sequence of ~N~ positive integers ~A_1~, ~A_2~, ~...~, ~A_N~, and an integer ~X~ are given. Write a program to find the number of pairs ~(A_i,\; A_j)~, where ~1 \le i < j \le N~ and ~A_i + A_j = X~.

Input

The first line of the input contains two numbers ~N~ and ~X~, separated by a single space. The second line contains the ~N~ integers ~A_i~ of the sequence, separated in pairs by spaces.

Output

The output should consist of a single line containing exactly one integer: the desired number of pairs.

Constraints

~1 \le N \le 1.000.000~
~1 \le X \le 2.000.000~
~1 \le A_i \le 1.000.000~
Execution time limit: 1 sec.
Memory limit: 64 MB.

Examples of Input - Output Files:

1st

STDIN (sumx.in)

9 13
5 12 7 10 9 1 2 3 11

STDOUT (sumx.out)

3

Explanation of the first example: In the first example, the possible pairs are three:

~A_2 + A_6 = 12 + 1 = 13~
~A_4 + A_8 = 10 + 3 = 13~
~A_7 + A_9 = 2 + 11 = 13~

2nd

STDIN (sumx.in)

5 12
1 2 3 4 6

STDOUT (sumx.out)

0

Explanation of the second example: In the second example, there is no pair that sums up to ~12~.

3d

STDIN (sumx.in)

6 10
2 4 6 8 4 6

STDOUT (sumx.out)

5

Explanation of the third example: Finally, in the third example, the possible pairs are five (pay attention to the repeating terms):

~A_1 + A_4 = 2 + 8 = 10~
~A_2 + A_3 = 4 + 6 = 10~
~A_2 + A_6 = 4 + 6 = 10~
~A_3 + A_5 = 6 + 4 = 10~
~A_5 + A_6 = 4 + 6 = 10~