#include<iostream>
using namespace std;
void inverse_order(int a[],int l,int r)
{ int sum=0;
if(l>=r)return ;
int mid=(l+r)/2;
inverse_order(a,l,mid),inverse_order(a,mid+1,r);
int i=l, j=mid+1, temp[100000],k=0;
while(i<=mid&&j<=r)
{
while(a[i]<a[j])temp[k++]=a[i++];
while(a[i]>a[j])
{ sum+=mid+1-i;
temp[k++]=a[j++];
};
}
while(i<mid)temp[k++]=a[i++];
while(j<r)temp[k++]=a[j++];
for(int i=l;i<r;i++)
a[i]=temp[i];
}