

#include<iostream>
using namespace std;
const int N = 100010;
int n, m;
int q[N], tmp[N];
long long merge_sort(int q[], int l, int r) {
if (l >= r) {
return 0;
}
int mid = (l + r) / 2;
long long ans = 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 {
ans += mid - i + 1;
tmp[k++] = q[j++];
}
}
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 ans;
}
int main() {
cin >> n;
for (int i = 0; i < n; i++) {
cin >> q[i];
}
long long num = merge_sort(q, 0, n - 1);
cout << num << endl;
return 0;
}