include [HTML_REMOVED]

using namespace std;
const int N = 1e3;
int q[N]; int temp[N];
typedef long long LL;
int n;
LL merge_sort(int l,int r)
{
if (l >= r) return 0;
int mid = l + r >> 1;
LL res = merge_sort(l, mid) + merge_sort(mid + 1, r); //
int k = 0, i = l, j = mid + 1;
while (i <= mid && j <= r)
{
if (q[i] <= q[j]) temp[k] = q[i];
else
{
temp[k] = q[j];
res += mid - i + 1; //
};
};
while (i <= mid) temp[k] = q[i];
while (j <= r) temp[k] = q[j];
for (int i = l, j = 0; i < n; i, j)
{
q[i] = temp[j];
};
return res;
}
int main()
{

cin >> n;
for (int i = 0; i < n; i++) cin >> q[i];
cout << merge_sort(0, n - 1) << endl;

}