#include #include using namespace std; using namespace atcoder; #define rep(i, n) REP(i, 0, n) #define REP(i, s, e) for (int i = (s); i < (int)(e); i++) #define repr(i, n) REPR(i, n, 0) #define REPR(i, s, e) for (int i = (int)(s - 1); i >= (int)(e); i--) #define all(r) r.begin(), r.end() #define rall(r) r.rbegin(), r.rend() typedef long long ll; typedef vector vi; typedef vector vl; template T chmax(T& a, const U& b) { if (a >= b) return false; a = b; return true; } template T chmin(T& a, const U& b) { if (a <= b) return false; a = b; return true; } void yes_no(bool f, string yes = "Yes", string no = "No") { cout << (f ? yes : no) << "\n"; } void solve() { int n; cin >> n; vl a(n); map mp; rep(i, n) cin >> a[i], mp[a[i]]++; auto f = [&](const vl& a) { vi idx(n); rep(i, n) idx[i] = i; sort(all(idx), [&](int idx_i, int idx_j) { return a[idx_i] != a[idx_j] ? a[idx_i] < a[idx_j] : idx_i > idx_j; }); segtree seg(n); vl res(n); for (auto&& i : idx) { if (i > 0) res[i] = seg.prod(0, i); seg.set(i, 1); } return res; }; ll ans = n * (n - 1) * (n - 2) / 6; { auto b = a; auto x = f(b); rep(i, n) b[i] = -b[i]; reverse(all(b)); auto y = f(b); reverse(all(y)); REP(i, 1, n) { ans -= x[i] * y[i]; } } { auto b = a; rep(i, n) b[i] = -b[i]; auto x = f(b); rep(i, n) b[i] = -b[i]; reverse(all(b)); auto y = f(b); reverse(all(y)); REP(i, 1, n) { ans -= x[i] * y[i]; } } for (auto&& [k, v] : mp) { if (v >= 2) { ans -= v * (v - 1) / 2 * (n - v); } if (v >= 3) { ans -= v * (v - 1) * (v - 2) / 6; } } cout << ans << "\n"; } int main() { cin.tie(0); ios::sync_with_stdio(false); int t = 1; // multi-testcase // cin >> t; rep(ti, t) solve(); return 0; }