#include #include #include using namespace std; using namespace atcoder; using mint = modint998244353; void fast_io() { ios::sync_with_stdio(false); std::cin.tie(nullptr); } mint fact[1 << 21], fact_inv[1 << 21]; void calc_fact() { fact[0] = 1; for (int i = 1; i < (1 << 21); i++) { fact[i] = fact[i - 1] * i; } fact_inv[(1 << 21) - 1] = fact[(1 << 21) - 1].inv(); for (int i = (1 << 21) - 1; i >= 1; i--) { fact_inv[i - 1] = fact_inv[i] * i; } } mint binom(int n, int k) { if (n < k) { return 0; } return fact[n] * fact_inv[n - k] * fact_inv[k]; } int main() { fast_io(); calc_fact(); int n; cin >> n; vector p(n); for (int i = 0; i < n; i++) { cin >> p[i]; p[i]--; } fenwick_tree fw_fr(n), fw_bk(n); for (int i = 0; i < n; i++) { fw_bk.add(i, 1); } mint ans = 0; for (int i = 0; i < n; i++) { int a = fw_fr.sum(p[i] + 1, n), b = fw_fr.sum(0, p[i]); int c = fw_bk.sum(p[i] + 1, n), d = fw_bk.sum(0, p[i]); ans += binom(a + d, a) * binom(b + c, b); fw_fr.add(p[i], 1); fw_bk.add(p[i], -1); } cout << ans.val() << endl; }