P2560 [CF582C] Superior Periodic Subarrays
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题目描述

You are given an infinite periodic array a0, a1, ..., an - 1, ... with the period of length n. Formally, $$a_{i} = a_{i \bmod n}$$. A periodic subarray (l, s) (0 ≤ l < n, 1 ≤ s < n) of array a is an infinite periodic array with a period of length s that is a subsegment of array a, starting with position l.

A periodic subarray (l, s) is superior, if when attaching it to the array a, starting from index l, any element of the subarray is larger than or equal to the corresponding element of array a. An example of attaching is given on the figure (top — infinite array a, bottom — its periodic subarray (l, s)):

Find the number of distinct pairs (l, s), corresponding to the superior periodic arrays.

Input

The first line contains number n (1 ≤ n ≤ 2·105). The second line contains n numbers a0, a1, ..., an - 1 (1 ≤ ai ≤ 106), separated by a space.

Output

Print a single integer — the sought number of pairs.

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
4 7 1 2 3
样例输出
2
提示

In the first sample the superior subarrays are (0, 1) and (3, 2).

Subarray (0, 1) is superior, as a0 ≥ a0, a0 ≥ a1, a0 ≥ a2, a0 ≥ a3, a0 ≥ a0, ...

Subarray (3, 2) is superior a3 ≥ a3, a0 ≥ a0, a3 ≥ a1, a0 ≥ a2, a3 ≥ a3, ...

In the third sample any pair of (l, s) corresponds to a superior subarray as all the elements of an array are distinct.