题目描述
Given an array A of N integers. Find total number of pairs such that i < j and A[i] > A[j].
Constraints
1 ≤ N ≤ 2*10^3
1 ≤ Ai ≤ 10^9
SAMPLE INPUT
5
5 1 2 4 3
SAMPLE OUTPUT
5
输入格式
见题面
输出格式
见题面
样例输入
5
5 1 2 4 3
SAMPLE
样例输出
5
Given an array A of N integers. Find total number of pairs such that i < j and A[i] > A[j].
Constraints
1 ≤ N ≤ 2*10^3
1 ≤ Ai ≤ 10^9
SAMPLE INPUT
5
5 1 2 4 3
SAMPLE OUTPUT
5
见题面
见题面