180. Inversions

time limit per test: 0.50 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

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Author:Stanislav Angelyuk

Resource:Saratov ST team Spring Contest #1

Date:18.05.2003












 
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