eolymp
bolt
Try our new interface for solving problems
Problems

United Cows of Farmer John (Platinum)

United Cows of Farmer John (Platinum)

The United Cows of Farmer John (UCFJ) are sending a delegation to the International bOvine olympIad (IOI).

There are n cows participating in delegation selection. They are standing in a line, and cow i has breed bi.

The delegation will consist of a contiguous interval of at least three cows - that is, cows l..r for integers l and r satisfying 1l < rn and rl2. Three of the cows in the chosen interval are marked as delegation leaders. For legal reasons, the two outermost cows of the chosen interval must be leaders. Moreover, to avoid intra-breed conflict, every leader must be of a different breed from the rest of the delegation (leaders or not).

Help the UCFJ determine (for tax reasons) the number of ways they might choose a delegation to send to the IOI. Two delegations are considered different if they have different members or different leaders.

Input

The first line contains n (1n2 * 105).

The second line contains n integers b1, b2, .., bn, each in the range [1, n].

Output

Print the number of possible delegations, on a single line.

Note that the large size of integers involved in this problem may require the use of 64-bit integer data types (e.g., a "long long" in C/C++).

Example

Each delegation corresponds to one of the following triples of leaders:

(1, 2, 3), (1, 2, 4), (1, 3, 4), (1, 4, 7), (2, 3, 4), (4, 5, 6), (4, 5, 7), (4, 6, 7), (5, 6, 7).

Time limit 1 second
Memory limit 128 MiB
Input example #1
7
1 2 3 4 3 2 5
Output example #1
9
Source 2021 USACO US Open, Platinum