180. Inversions

time limit per test: 0.25 sec.
memory limit per test: 4096 KB
input: standard
output: standard



There are N integers (1<=N<=65537) A1, A2,.. AN (0<=Ai<=10^9). You need to find amount of such pairs (i, j) that 1<=i<j<=N and A[i]>A[j].

Input
The first line of the input contains the number N. The second line contains N numbers A1...AN.

Output
Write amount of such pairs.

Sample test(s)

Input
5 
2 3 1 5 4 

Output
3 
  
  
Author:Stanislav Angelyuk 
Resource:Saratov ST team Spring Contest #1 
Date:18.05.2003