## An Inversion Problem

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Points: 10
Time limit: 2.0s
Memory limit: 64M

Author:
Problem type

Given a permutation of the integers to , print out the number of inversions in the array.

An inversion is defined as a pair of indices, such that .

#### Input Specification

The first line will contain the integer .

The second line will contain integers, .

It is guaranteed the second line will contain a valid permutation of the integers from to .

#### Output Specification

Output the number of inversions in the permutation.

#### Sample Input

4
3 2 1 4

#### Sample Output

3