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
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