#P1693D. Decinc Dividing

    ID: 1044 Type: RemoteJudge 2000ms 256MiB Tried: 0 Accepted: 0 Difficulty: 10 Uploaded By: Tags>brute forcedata structuresdivide and conquerdpgreedy*2800

Decinc Dividing

Description

Let's call an array aa of mm integers a1,a2,,ama_1, a_2, \ldots, a_m Decinc if aa can be made increasing by removing a decreasing subsequence (possibly empty) from it.

  • For example, if a=[3,2,4,1,5]a = [3, 2, 4, 1, 5], we can remove the decreasing subsequence [a1,a4][a_1, a_4] from aa and obtain a=[2,4,5]a = [2, 4, 5], which is increasing.

You are given a permutation pp of numbers from 11 to nn. Find the number of pairs of integers (l,r)(l, r) with 1lrn1 \le l \le r \le n such that p[lr]p[l \ldots r] (the subarray of pp from ll to rr) is a Decinc array.

The first line contains a single integer nn (1n21051 \le n \le 2 \cdot 10^5)  — the size of pp.

The second line contains nn integers p1,p2,,pnp_1, p_2, \ldots, p_n (1pin1 \le p_i \le n, all pip_i are distinct)  — elements of the permutation.

Output the number of pairs of integers (l,r)(l, r) such that p[lr]p[l \ldots r] (the subarray of pp from ll to rr) is a Decinc array. (1lrn)(1 \le l \le r \le n)

Input

The first line contains a single integer nn (1n21051 \le n \le 2 \cdot 10^5)  — the size of pp.

The second line contains nn integers p1,p2,,pnp_1, p_2, \ldots, p_n (1pin1 \le p_i \le n, all pip_i are distinct)  — elements of the permutation.

Output

Output the number of pairs of integers (l,r)(l, r) such that p[lr]p[l \ldots r] (the subarray of pp from ll to rr) is a Decinc array. (1lrn)(1 \le l \le r \le n)

Sample Input 1

3
2 3 1

Sample Output 1

6

Sample Input 2

6
4 5 2 6 1 3

Sample Output 2

19

Sample Input 3

10
7 10 1 8 3 9 2 4 6 5

Sample Output 3

39

Note

In the first sample, all subarrays are Decinc.

In the second sample, all subarrays except p[16]p[1 \ldots 6] and p[26]p[2 \ldots 6] are Decinc.