include[HTML_REMOVED]

using namespace std;
const int N=100010;
int q[N],tmp[N];
unsigned long long merge_sort(int q[],int l,int r) //返回逆序数
{
if (l>=r) return 0;
else
{
int mid=(l+r)>>2;
unsigned long long res=0;
res+=merge_sort(q,l,mid);
res+=merge_sort(q,mid+1,r);

    int i=l, j=mid+1,k=0;
    while (i<=mid && j<=r)
    {
        if(q[i]>q[j])  { tmp[k++]=q[j++]; res+=mid-i+1;}
        else tmp[k++]=q[i++];

    }
    while (i<=mid) tmp[k++]=q[i++];
    while (j<=r) tmp[k++]=q[j++];

    for (int i=l,j=0;i<=r;i++,j++)
    {
        q[i]=tmp[j];
    }
    return res;

}

}

int main()
{
int n;
cin>>n;
for (int i=0;i[HTML_REMOVED]>q[i];
}
cout<<merge_sort(q,0,n-1);
return 0;

}