OpenKattis
AAPS18 Session 02

#### Start

2018-02-08 03:10 AKST

## AAPS18 Session 02

#### End

2018-02-08 06:30 AKST
The end is near!
Session is over.
Not yet started.
Session is starting in -1082 days 0:34:34

3:20:00

0:00:00

# Problem DUltra-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.

## Input

Input begins with a line that contains a single integer $1 \le n \le 500\, 000$ – the length of the input sequence. Each of the the following $n$ lines contains a single integer $0 \le a[i] \le 999\, 999\, 999$, the $i$-th input sequence element.

## Output

Prints a single line containing an integer number op, the minimum number of swap operations necessary to sort the given input sequence.

Sample Input 1 Sample Output 1
5
9
1
0
5
4

6

Sample Input 2 Sample Output 2
3
1
2
3

0