include[HTML_REMOVED]
using namespace std;
const int N = 100010;
typedef long long LL;
int n;
int q[N],tmp[N];
LL merge_sort(int q[], int l, int r)
{
if (l >= r) return 0;
int mid = l + r >> 1;
LL res = merge_sort(q, l, mid) + merge_sort(q, mid + 1, r);
int k = 0, i = l, j = mid + 1;
while(i <= mid && j <= r)
if(q[i] <= q[j]) tmp[k++] = q[i++];
else
{
tmp[k++] = q[j++];
res += mid - i + 1;
}
while(i <= mid) tmp[k++] = q[i++];
while(j <= r) tmp[k++]= q[j++];
for(i = l, j = 0; i <= r; i++, j++) q[i] = tmp[j];
return res;
}
int main()
{
scanf(“%d”,&n);
for(int i = 0; i < n; i++) scanf(“%d”,&q[i]);
cout << merge_sort(q, 0, n-1) << endl;
return 0;
}