#include #include #include #include #include #include #include #include #define rep(i, a, b) for (int i = int(a); i < int(b); i++) using namespace std; using ll = long long int; // NOLINT using P = pair; // clang-format off #ifdef _DEBUG_ #define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; debug_print(__VA_ARGS__); } while(false) template void debug_print(const T &t, const Ts &...ts) { cerr << t; ((cerr << ", " << ts), ...); cerr << endl; } #else #define dump(...) do{ } while(false) #endif template vector make_v(size_t a, T b) { return vector(a, b); } template auto make_v(size_t a, Ts... ts) { return vector(a, make_v(ts...)); } template bool chmin(T &a, const T& b) { if (a > b) {a = b; return true; } return false; } template bool chmax(T &a, const T& b) { if (a < b) {a = b; return true; } return false; } template void print(const T& t, const Ts&... ts) { cout << t; ((cout << ' ' << ts), ...); cout << '\n'; } template void input(Ts&... ts) { (cin >> ... >> ts); } template istream &operator,(istream &in, T &t) { return in >> t; } struct Inf { template constexpr operator T() { return numeric_limits::max() / 2; } }; // clang-format on #include int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n; cin, n; vector a(n); rep(i, 0, n) { cin, a[i]; } int r = 0; multiset s; auto check = [&](int v) { if (s.size() < 1) return true; auto it = s.insert(v); auto first = s.begin(); auto second = next(first); auto last = s.rbegin(); bool res = *last <= *first + *second; s.erase(it); return res; }; ll ans = 0; rep(l, 0, n) { while (r < n && check(a[r])) { s.insert(a[r]); r++; } dump(l, r, s.size()); ans += r - l - 1; auto rm = s.find(a[l]); s.erase(rm); } print(ans); return 0; }