#include #include #include #include #include #include #include #include #include #include using namespace std; #define int long long int MOD = 1000000007; template struct fenwick_tree { vector x; fenwick_tree(int n) : x(n, 0) { } T sum(int i, int j) { if (i == 0) { T S = 0; for (j; j >= 0; j = (j & (j + 1)) - 1) S += x[j]; return S; } else return sum(0, j) - sum(0, i - 1); } void add(int k, T a) { for (; k < x.size(); k |= k + 1) x[k] += a; } }; signed main() { cin.tie(0); ios::sync_with_stdio(false); int N; cin >> N; vector A(N); int res = 0; for (int i = 0; i < N; i++) { cin >> A[i]; //A[i] = N - i; A[i]--; } fenwick_tree ft(N); for (int i = 0; i < N; i++) { ft.add(i, 1); } for (int i = 0; i < N - 1; i++) { int k = ft.sum(0, A[i] - 1); ft.add(A[i], -1); //cerr << k << endl; res += k; res *= N - i - 1; } //cout << ((res + 1) - res) << endl; //bigint x = 1; res++; cout << res << endl; }