#include <iostream>

using namespace std;

const int N = 100010;

int n;
int tmp[N], q[N];
long ans = 0;

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

int main() {
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> q[i];
    f(1, n);
    cout << ans << endl;

    return 0;
}