#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdint>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <sys/timeb.h>
#include <vector>

using namespace std;

#define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repr(i, 0, n)
#define reprrev(i, a, b) for (int i = (int)(b)-1; i >= (int)(a); i--)
#define reprev(i, n) reprrev(i, 0, n)
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define chmin(mi, val) mi = min(mi, val)
#define chmax(ma, val) ma = max(ma, val)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define mp make_pair
#define mt make_tuple
#define INF 1050000000
#define INFR INT_MAX
#define INFL (long long)(4e18)
#define INFLR LLONG_MAX
#define EPS (1e-10)
#define MOD 1000000007
//#define MOD 998244353
#define PI 3.141592653589793238
#define RMAX 4294967295

using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvvi = vector<vector<vector<int>>>;
using vvvvi = vector<vector<vector<vector<int>>>>;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
using vvvll = vector<vector<vector<ll>>>;
using vd = vector<double>;
using vvd = vector<vector<double>>;
using vb = vector<bool>;
using vvb = vector<vector<bool>>;
using vc = vector<char>;
using vvc = vector<vector<char>>;
using vs = vector<string>;
using vvs = vector<vector<string>>;
using Pi = pair<int, int>;
using vPi = vector<Pi>;
using vvPi = vector<vector<Pi>>;
using vvvPi = vector<vector<vector<Pi>>>;
using vvvvPi = vector<vector<vector<vector<Pi>>>>;
using Pll = pair<ll, ll>;
using vPll = vector<Pll>;
using Pd = pair<double, double>;
using vPd = vector<Pd>;
template <class T>
using vec = vector<T>;
template <class T>
using pql = priority_queue<T, vector<T>, greater<T>>;
using Comp = complex<double>;

// vvvvvvvvvvvvvvvvvvvvvvv debug output vvvvvvvvvvvvvvvvvvvvvvv
// vector input
template <typename T>
istream &operator>>(istream &is, vector<T> &vec) {
    for (T &x : vec) is >> x;
    return is;
}
// pair
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &pair_var) {
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}
// vector
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
    os << "{";
    for (int i = 0; i < vec.size(); i++) {
        os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
    }
    os << "}";
    return os;
}
// deque
template <typename T>
ostream &operator<<(ostream &os, const deque<T> &vec) {
    os << "{";
    for (int i = 0; i < vec.size(); i++) {
        os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
    }
    os << "}";
    return os;
}
// map
template <typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &map_var) {
    os << "{";
    repi(itr, map_var) {
        os << *itr;
        itr++;
        if (itr != map_var.end()) os << ", ";
        itr--;
    }
    os << "}";
    return os;
}
// set
template <typename T>
ostream &operator<<(ostream &os, const set<T> &set_var) {
    os << "{";
    repi(itr, set_var) {
        os << *itr;
        itr++;
        if (itr != set_var.end()) os << ", ";
        itr--;
    }
    os << "}";
    return os;
}
// multiset
template <typename T>
ostream &operator<<(ostream &os, const multiset<T> &set_var) {
    os << "{";
    repi(itr, set_var) {
        os << *itr;
        itr++;
        if (itr != set_var.end()) os << ", ";
        itr--;
    }
    os << "}";
    return os;
}

#define DUMPOUT cerr

void dump_func() {
    DUMPOUT << endl;
}
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&... tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) > 0) {
        DUMPOUT << ", ";
    }
    dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \
    DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                            \
            << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]"        \
            << endl                                                            \
            << "    ",                                                         \
        dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

// ^^^^^^^^^^^^^^^^^^^^^^^ debug output ^^^^^^^^^^^^^^^^^^^^^^^

string YN(bool y, int id = 0) {
    if (id) cout << id;
    return (y ? "YES" : "NO");
}
string yn(bool y, int id = 0) {
    if (id) cout << id;
    return (y ? "Yes" : "No");
}
string ON(bool y, int id = 0) {
    if (id) cout << id;
    return (y ? "OK" : "NG");
}

int dir4[4][2] = {{0, -1}, {-1, 0}, {1, 0}, {0, 1}};
int dir8[8][2] = {{-1, -1}, {0, -1}, {1, -1}, {-1, 0},
                  {1, 0},   {-1, 1}, {0, 1},  {1, 1}};
char dirchar[4] = {'<', '^', '>', 'v'};

// [a,b)
int irand(int a, int b) {
    static mt19937 Rand(static_cast<unsigned int>(time(nullptr)));
    uniform_int_distribution<int> dist(a, b - 1);
    return dist(Rand);
}

// [a,b)
double drand(int a, int b) {
    static mt19937 Rand(static_cast<unsigned int>(time(nullptr)));
    uniform_real_distribution<double> dist(a, b);
    return dist(Rand);
}

// https://qiita.com/IgnorantCoder/items/3101d6276e9bdddf872c
template <typename A, typename F>
inline auto transform(const A &v, F &&f) {
    using result_type =
        decltype(std::declval<F>()(std::declval<typename A::value_type>()));
    vector<result_type> y(v.size());
    std::transform(std::cbegin(v), std::cend(v), std::begin(y), f);
    return y;
}

// 多次元vector生成
template <class T>
vector<T> make_v(size_t size, const T &init) {
    return vector<T>(size, init);
}
template <class... Ts>
auto make_v(size_t size, Ts... rest) {
    return vector<decltype(make_v(rest...))>(size, make_v(rest...));
}

template <typename T>
T Max(vector<T> a) {
    return *max_element(all(a));
}
template <typename T>
T Min(vector<T> a) {
    return *min_element(all(a));
}
template <typename T>
T Sum(vector<T> a) {
    return accumulate(all(a), (T)0);
}

// mapでカウントとかする
template <typename T>
void Add(map<T, int> &m, T item) {
    if (m.find(item) == m.end()) {
        m[item] = 1;
    } else {
        m[item]++;
    }
}

// mapでカウントとかする
template <typename T>
void Erase(map<T, int> &m, T item) {
    if (m.find(item) == m.end()) {
    } else {
        if (m[item] == 1) {
            m.erase(item);
        } else {
            m[item]--;
        }
    }
}

// デフォルト値つきのmapのget
template <typename T, typename U>
U Get(map<T, U> m, T key, U def) {
    if (m.find(key) == m.end()) {
        return def;
    } else {
        return m[key];
    }
}

template <typename T>
inline bool Contains(const set<T> &t, const T &key) {
    return t.find(key) != t.end();
}

template <typename T, typename U>
inline bool Contains(const map<T, U> &t, const T &key) {
    return t.find(key) != t.end();
}

template <class T>
struct Edge {
    int from, to;
    T cost;
    bool operator<(Edge e) {
        return cost < e.cost;
    }
};

template <class T>
ostream &operator<<(ostream &os, Edge<T> &edge) {
    os << "(" << edge.from << "->" << edge.to << ":" << edge.cost << ")";
    return os;
}
template <class T = int>
class Graph {
    int n;
    bool directed;
    vector<vector<Edge<T>>> edges;

  public:
    Graph(int n, bool directed)
        : n(n), directed(directed), edges(vector<vector<Edge<T>>>(n)) {}

    void add_edge(int s, int t, T cost) {
        edges[s].push_back(Edge<T>{s, t, cost});
        if (!directed) {
            edges[t].push_back(Edge<T>{t, s, cost});
        }
    }
    Graph() {}

    vector<Edge<T>> operator[](size_t i) const {
        return edges[i];
    }

    int size() const {
        return n;
    }
};

//======================================================

template <class T>
class SegTree {
    int n;                       // 葉の数
    vector<T> data;              // データを格納するvector
    T def;                       // 初期値かつ単位元
    function<T(T, T)> operation; // 区間クエリで使う処理
    function<T(T, T)> update;    // 点更新で使う処理

    // 区間[a,b)の総和。ノードk=[l,r)に着目している。
    T _query(int a, int b, int k, int l, int r) const {
        if (r <= a || b <= l) return def; // 交差しない
        if (a <= l && r <= b)
            return data[k]; // a,l,r,bの順で完全に含まれる
        else {
            T c1 = _query(a, b, 2 * k + 1, l, (l + r) / 2); // 左の子
            T c2 = _query(a, b, 2 * k + 2, (l + r) / 2, r); // 右の子
            return operation(c1, c2);
        }
    }

  public:
    // _n:必要サイズ, _def:初期値かつ単位元, _operation:クエリ関数,
    // _update:更新関数
    SegTree(size_t _n, T _def, function<T(T, T)> _operation,
            function<T(T, T)> _update)
        : def(_def), operation(_operation), update(_update) {
        n = 1;
        while (n < _n) {
            n *= 2;
        }
        data = vector<T>(2 * n - 1, def);
    }

    // 場所i(0-indexed)の値をxで更新
    void change(int i, T x) {
        i += n - 1;
        data[i] = update(data[i], x);
        while (i > 0) {
            i = (i - 1) / 2;
            data[i] = operation(data[i * 2 + 1], data[i * 2 + 2]);
        }
    }

    // [a, b)の区間クエリを実行
    T query(int a, int b) const {
        return _query(a, b, 0, 0, n);
    }

    // 添字でアクセス
    T operator[](int i) const {
        return data[i + n - 1];
    }
};

int N;

ll calc(int idx, SegTree<int> &st) {
    // P[idx] が 2 番目になる区間の数
    ll ans = 0;

    // [l1, idx) の最大値が P[idx] を超える最大の l1
    int ok = -1, ng = idx;
    while (ng - ok > 1) {
        int mid = (ok + ng) / 2;
        if (st.query(mid, idx) > st[idx]) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    int l1 = ok;

    // [l2, l1) の最大値が P[idx] を超える最大の l2
    ok = -1, ng = l1;
    while (ng - ok > 1) {
        int mid = (ok + ng) / 2;
        if (st.query(mid, l1) > st[idx]) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    int l2 = ok;

    // [idx, r1) の最大値が P[idx] を超える最小の r1
    ok = N + 1, ng = idx;
    while (ok - ng > 1) {
        int mid = (ok + ng) / 2;
        if (st.query(idx, mid) > st[idx]) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    int r1 = ok;

    // [r1, r2) の最大値が P[idx] を超える最小の r2
    ok = N + 1, ng = r1;
    while (ok - ng > 1) {
        int mid = (ok + ng) / 2;
        if (st.query(r1, mid) > st[idx]) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    int r2 = ok;

    dump(l2, l1, idx, r1, r2);

    return (ll)(l1 - l2) * (r1 - 1 - idx) + (ll)(idx - l1) * (r2 - r1);
}

int main() {
    cin >> N;
    vi P(N);
    cin >> P;
    SegTree<int> st(N, 0, [](int a, int b) { return max(a, b); },
                    [](int a, int b) { return b; });
    rep(i, N) {
        st.change(i, P[i]);
    }

    ll ans = 0;
    rep(i, N) {
        ll c = calc(i, st);
        dump(c);
        ans += (ll)P[i] * c;
    }
    cout << ans << endl;

    return 0;
}

Measured memory_bytes: 1664