include[HTML_REMOVED]

using namespace std;
typedef long long LL;
const int N = 100010;

int n;
int q[N],tmp[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);

//归并的过程
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;
    }
    //扫尾
    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 ()
{
cin >> n;
for(int i=0 ;i < n ;i++){
cin >> q[i];
}
cout << merge_sort(0, n-1) << endl;
}