#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

class BinaryIndexTree {
public:
  vector<ll> data;
  BinaryIndexTree(ll size) {
    data.resize(size, 0);
  }
  void add(ll i, ll x) {
    i++;
    ll n = data.size();
    while (i <= n) {
      data[i - 1] += x;
      i += i & -i;
    }
  }
  ll sum(ll stop) {
    ll result = 0;
    ll i = stop;
    while (i > 0) {
      result += data[i - 1];
      i -= i & -i;
    }
    return result;
  }
  ll range_sum(ll start, ll stop) {
    return sum(stop) - sum(start); 
  }
};

int main() {
  int N; cin >> N;
  vector<int> P(N);
  for (auto &x: P) cin >> x;
  BinaryIndexTree bit(N + 1);
  ll result = 0;
  for (auto x: P) {
    result += bit.range_sum(x + 1, N + 1);
    bit.add(x, 1);
  }
  cout << result << endl;
  return 0;
}