A Pair of Good Things

Problem Description

Dazhi's father has finished his engineering project smoothly, and his mother has been promoted to manager — truly a pair of good things. To celebrate, Dazhi's father wants to set Dazhi a problem (poor Dazhi). We now define a "good-thing pair": for two numbers $a, b$, if $a=2b$ or $b=2a$ holds, then $a$ and $b$ are said to be a "good-thing pair". Given an array, count how many good-thing pairs it contains.

Input Format

A sequence of positive integers, each not exceeding $99$ and all distinct, ending with the number $0$ to mark the end of input.

Output Format

Output one integer as the answer.

Sample Input

1 4 3 2 9 7 18 22 0

Sample Output

3

Hint

1 4 3 2 9 7 18 22 0

There are $3$ pairs in total: $2$ and $1$, $4$ and $2$, $18$ and $9$.