#532
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United Cows of Farmer John
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문제

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

There are NN cows participating in delegation selection (1N21051 \leq N \leq 2 \cdot 10^5). They are standing in a line, and cow ii has breed bib_i.

The delegation will consist of a contiguous interval of at least three cows - that is, cows lrl\ldots r for integers ll and rr satisfying 1l<rN1\le l<r\le N and rl2r-l\ge 2. 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.

입력

The first line contains NN.

The second line contains NN integers b1,b2,,bNb_1,b_2,\ldots,b_N, each in the range [1,N][1,N].

출력

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++).

예제 입력 1

7
1 2 3 4 3 2 5

예제 출력 1

9

점수

Test cases 1-2 satisfy N50N\le 50.Test cases 3-4 satisfy N500N\le 500.Test cases 5-8 satisfy N5000N\le 5000.Test cases 9-20 satisfy no additional constraints.

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