Enemy is weak

TimeLimit:5000MS  MemoryLimit:256MB
64-bit integer IO format:%I64d
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Problem Description

The Romans have attacked again. This time they are much more than the Persians but Shapur is ready to defeat them. He says: "A lion is never afraid of a hundred sheep".

Nevertheless Shapur has to find weaknesses in the Roman army to defeat them. So he gives the army a weakness number.

In Shapur's opinion the weakness of an army is equal to the number of triplets i, j, k such that i < j < k and ai > aj > ak where ax is the power of man standing at position x. The Roman army has one special trait — powers of all the people in it are distinct.

Help Shapur find out how weak the Romans are.

Input

The first line of input contains a single number n (3 ≤ n ≤ 106) — the number of men in Roman army. Next line contains n different positive integers ai (1 ≤ i ≤ n, 1 ≤ ai ≤ 109) — powers of men in the Roman army.

Output

A single integer number, the weakness of the Roman army.

Please, do not use %lld specificator to read or write 64-bit integers in C++. It is preffered to use cout (also you may use %I64d).

SampleInput 1
3
3 2 1
SampleOutput 1
1
SampleInput 2
3
2 3 1
SampleOutput 2
0
SampleInput 3
4
10 8 3 1
SampleOutput 3
4
SampleInput 4
4
1 5 4 3
SampleOutput 4
1
Submit
题目统计信息详细
总AC数46
通过人数30
尝试人数33
总提交量93
AC率32.26%
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