E. Enemy is weak
time limit per test
5 seconds
memory limit per test
256 megabytes
output
standard output
罗马人又进攻了。这次他们比波斯人强得多，但沙普尔已经准备好击败他们。他说：“狮子不怕一百只羊”。
然而，沙普尔必须找到罗马军队的弱点来击败他们。所以他给了军队一个弱点号码。
沙普尔认为，军队的弱点等于三元组i、j、k的数量，因此i＜j＜k和ai＞aj＞ak，其中ax是站在x位置的人的力量。
帮助沙普尔了解罗马人有多软弱。
输入
第一行输入包含单个数字n（3≤n≤1e6），即罗马军队中的人数。下一行包含n个不同的正整数ai（1≤i≤n，1≤ai≤1e9）——罗马军队中的男性力量。
输出
一个整数，罗马军队的弱点。
请不要使用%lld说明符在C++中读取或写入64位整数。建议使用cout（也可以使用%I64d）。
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.
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).