In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. For the input sequence
9, 1, 0, 5, 4
Ultra-QuickSort produces the output
0, 1, 4, 5, 9
Your task is to determine how many swap operations Ultra-QuickSort needs to perform in order to sort a given input sequence.
The input contains several test cases. Every test case begins with a line that contains a single integer \(n < 5\times10^5\) : the length of the input sequence. Each of the the following \(n\) lines contains a single integer \(0 \le a_i < 10^9\), the i-th input sequence element. Input is terminated by a sequence of length \(n = 0\). This sequence must not be processed.
For every input sequence, your program prints a single line containing an integer number op, the minimum number of swap operations necessary to sort the given input sequence.
给定序列长度为 \(n (n \le 5\times 10^5)\)
5 9 1 0 5 4 3 1 2 3 0