## Problem B: Ultra-QuickSort

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 < 500,000* -- the length of the input
sequence. Each of the the following *n* lines contains a single integer
*0 ¡Ü a[i] ¡Ü 999,999,999*, 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.

### Sample Input

5
9
1
0
5
4
3
1
2
3
0

### Output for Sample Input

6
0

*Stefan Büttcher*