#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
ll const inf = 1e9;
ll const mod = 1e9 + 7;
ld const eps = 1e-13;

int a[1000001];
int idx[1000001];
int n;
ll bit[1000001];

ll sum(int k){
        ll s = 0;
        while(k > 0){
                s += bit[k];
                k -= k&-k;
        }
        return s;
}
void update(int k, int x){
            while(k <= n){
                        bit[k] += x;
                        k += k&-k;
            }
}
bool cmp(int i, int j){
        return a[i] < a[j];
}

int main()
{

        cin >> n;
        fr(i, 0, n){
                cin >> a[i];
                idx[i] = i;
        }
        sort(idx, idx + n, cmp);
        ll ans = 0;
        fr(i, 0, n){
                ans += (ll)sum(n) - sum(idx[i]);
                update(idx[i] + 1, 1);
        }
        cout << ans << endl;
        return 0;
}