#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>

struct Fenwick {
    int n;
    vector<ll> t;
    Fenwick(int n_) {
        n = n_; t.assign(n + 1, 0);
    }

    void change(int u, ll x) {
        for (; u <= n; u += u & -u) t[u] += x;
    }
    ll sum(int u) {
        ll sum = 0;
        for (; u; u -= u & -u) sum += t[u];
        return sum;
    }
    ll sum(int l, int r) {
        return sum(r) - sum(l - 1);
    }
};
void solve() {
    int n;
    cin >> n;

    Fenwick t(1e5);
    ll res = 0;
    for (int i = 1; i <= n; i++) {
        int x; cin >> x;
        res += t.sum(x + 1, 1e5);
        t.change(x, 1);
    }
    cout << res << '\n';
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    // cout << powl(1 - 1 / 1e9, 3e7) << '\n';
    int t = 1;
    while (t--)
        solve();
    return 0;
}
/*
g++ -std=c++20 1.cpp -o 1 && 1 < in.txt > out.txt
*/