E. Special Segments of Permutationtime limit per test2 secondsmemory limit per test512 megabytesinputstandard inputoutputstandard outputYou are given a permutation p of n integers 1, 2, ..., n (a permutation is an array where each element from 1 to n occurs exactly once).Let's call some subsegment p[l, r] of this permutation special if p_l + p_r = \max \limits_{i = l}^{r} p_i. Please calculate the number of special subsegments.InputThe first line contains one integer n (3 \le n \le 2 \cdot 10^5).The second line contains n integers p_1, p_2, ..., p_n (1 \le p_i \le n). All these integers are pairwise distinct.OutputPrint the number of special subsegments of the given permutation.ExamplesInput
5
3 4 1 5 2
Output
2
Input
3
1 3 2
Output
1
NoteSpecial subsegments in the first example are [1, 5] and [1, 3].The only special subsegment in the second example is [1, 3].
5
3 4 1 5 2

2 
['data structures', 'divide and conquer', 'dsu', 'two pointers', '*2200']