Fence Repair
题号:NC15941
时间限制:C/C++/Rust/Pascal 1秒,其他语言2秒
空间限制:C/C++/Rust/Pascal 128 M,其他语言256 M
64bit IO Format: %lld

题目描述

Founded in 1958, CSUFT has developed into a multidisciplinary university comprising a wide range of disciplines in science, engineering, agriculture, arts, law, economics, management and education, and has been authorized to offer a comprehensive range of programs including bachelor, master, doctor’s programs and post-doctoral programs. Since its foundation, the university has turned out over 160,000 talents. CSUFT is located in the national historical and cultural city : Changsha. 

The above is the history of our school. The next is the description of this problem ^_^.

Giving n numbers,Cyl want to find the answer how many pairs of these numbers meet the condition of Ai *2 = Aj (i < j). Please you tell him.

Please note that there are many groups of samples.

输入描述:

Line 1: Oneinteger N, the number of numbers. (1 < N <= 100)
Lines 2.....N+1: Each line contains a single integer ai. (0< ai < 100)

输出描述:

Line 1: One integer.
示例1

输入

复制
3
1
2
2

输出

复制
2