描述
Given a sequence of N number. How many numbers in the sequence are there which equal to the sum of two different numbers in the sequence.
输入
First line: one positive integers N (N <= 100).
Second line: N positive integers (<= 100000).
输出
One integer.
翻译:
给定一个N个数的序列。求序列中有多少个数等于序列中两个不同数的和。
输入:
第一行:一个正整数N
第二行:N个正整数
输出:
一个数。