#include <vector>
#include <iostream>
#include <cmath>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <fstream>
#include <unistd.h>
#include <string.h>
#include <string>
#include <numeric>
#include <queue>
#include <deque>
#include <sstream>
#include <iomanip>
#include <set>
#include <stack>
#include <cassert>
#include <functional>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef vector<string> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<char> vc;
typedef vector<vector<char>> vvc;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<vvd> vvvd;
typedef pair<ll, ll> PL;
typedef vector<PL> vpl;
typedef vector<vector<PL>> vvpl;
const int INF = 1001001001;
const ll LINF = 1e17;
const double pi = 3.1415926535897932;
const string endstr = "\n";
#define FOR(i, a, b) for(ll i = (a); i < b; i++)
#define RFOR(i, a, b) for(ll i = (a); i > b; i--)
#define rep(i, n) for(ll i = 0; i < n; i++)
#define rrep(i, n) for(ll i = n-1; i > -1; i--)
#define FORMAP(it, m) for(auto it = m.begin(); it != m.end(); it++)
#define ff first
#define ss second
#define pb push_back
#define epb emplace_back
#define ALL(X) (X).begin(),(X).end()

template <typename T>
T gcd(T a, T b) {
    return (a == 0) ? b : gcd(b%a, a);
}
template <typename T>
T lcm(T a, T b) {
    return a / gcd(a, b) * b;
}

bool p_comp_fs(const PL p1, const PL p2){ return p1.first < p2.first;};
bool p_comp_fg(const PL p1, const PL p2){ return p1.first > p2.first;};
bool p_comp_ss(const PL p1, const PL p2){ return p1.second < p2.second;};
bool p_comp_sg(const PL p1, const PL p2){ return p1.second > p2.second;};
template <typename T>
vector<T> uniquen(vector<T> vec){
    sort(ALL(vec));
    vec.erase(unique(vec.begin(), vec.end()), vec.end());
    return vec;
}

inline ll popcnt(ll x){return __builtin_popcountll((unsigned long long)x);};
template<class T> bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
//friend bool operator<(const stc& lhs, const stc& rhs){
//    return std::tie(lhs.l, lhs.r) < std::tie(rhs.l, rhs.r);
//}

template<typename Monoid>
struct SegmentTree {
    using F = function<Monoid(Monoid, Monoid) >;
    
    ll sz;
    vector<Monoid> seg;
    
    const F f;
    const Monoid M1;
    
    SegmentTree(ll n, const F f, const Monoid &M1) : f(f), M1(M1) {
        sz = 1;
        while(sz < n) sz <<= 1;
        seg.assign(2 * sz, M1);
    }
    
    void set(ll k, const Monoid &x) {
        seg[k + sz] = x;
    }
    
    void build() {
        for(ll k = sz - 1; k > 0; k--) {
            seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
        }
    }
    
    void update(ll k, const Monoid &x) {
        k += sz;
        seg[k] = x;
        while(k >>= 1) {
            seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
        }
    }
    
    Monoid query(ll a, ll b) {
        Monoid L = M1, R = M1;
        for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
            if(a & 1) L = f(L, seg[a++]);
            if(b & 1) R = f(seg[--b], R);
        }
        return f(L, R);
    }
    
    Monoid operator[](const ll &k) const {
        return seg[k + sz];
    }
};

// Usage:
// SegmentTree<ll> seg(L+1, [](ll a, ll b) { return min(a, b); }, LINF);

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll N; cin >> N;
    vpl P(N);
    rep(i, N){
        ll p; cin >> p; P[i] = {p, i+1};
    }
    sort(ALL(P), greater<PL>());
    
    auto seg = SegmentTree<ll>(N+2,
                               [](ll l, ll r){return l+r;}, 0);
    seg.update(0, LINF);
    seg.update(N+1, LINF);
    
    ll ans = 0;
    rep(i, N){
        ll idx = P[i].ss;
        
        vl ls(2), rs(2);
        rep(topk, 2){
            ll ok = idx-1, ng = N+2;
            while(abs(ok-ng)>1){
                ll mid = (ok+ng)/2;
                ll s = seg.query(idx+1, mid+1);
                if(s <= topk) ok = mid;
                else ng = mid;
            }
            rs[topk] = ok;
        }
        
       
        rep(topk, 2){
            ll ok = idx, ng = 0;
            while(abs(ok-ng)>1){
                ll mid = (ok+ng)/2;
                ll s = seg.query(mid, idx);
                if(s <= topk) ok = mid;
                else ng = mid;
            }
            ls[topk] = ok;
        }
        
        ll r1 = rs[1]-rs[0];
        ll l1 = idx-ls[0]+1;
        ll r2 = rs[0]-idx+1;
        ll l2 = ls[0]-ls[1];
        ans += P[i].ff*(abs(r1*l1) + abs(r2*l2));
        seg.update(idx, 1);
    }
    cout << ans << endstr;
    return 0;
}


Measured memory_bytes: 3840