#include <iostream>
using namespace std;
int main() {
    int n; cin >> n;
    int a[n]; for (int i = 0; i < n; i++) cin >> a[i];
    long long ans = 0;
    int bit[n+1] = {};
    for (int i = n-1; i >= 0; i--) {
        for (int x = a[i]; x > 0; x -= x&-x) ans += bit[x];
        for (int x = a[i]; x <= n; x += x&-x) bit[x]++;
    }
    cout << ans << endl;
}