|Author:||Иван Кобец||Time limit:||1 sec|
|Input file:||Standard input||Memory limit:||512 Mb|
|Output file:||Standard output|
The young programmer Ilya was presented with a sequence of numbers ai of length n for his birthday. Ilya decided to select fine segments from this sequence. A fine segment is a sequence of successive elements of ai containing some element equal to the sum of its first and last elements. For example, the sequence [1, 2, 5, 4] is fine because the sum of the leftmost and rightmost elements is 5, and the number 5 is in this sequence; the sequence [1, 2, 3, 4] is not fine because the sum of the leftmost and rightmost elements is 5, and the number 5 is not in this sequence. Your program must count the number of fine segments in a given sequence.
The first line contains an integer n — the length of the sequence. The second line contains n integers ai — the elements of the sequence. All elements of the sequence are different.
Output a single integer — number of fine segments in the sequence.
1 ≤ n ≤ 103
1 ≤ ai ≤ 105
First sample has one fine segment: [3, 7, 5, 4].
Second sample has two fine segments: [1, 5, 4] и [1, 5, 4, 7, 6].
|No.||Standard input||Standard output|