#include <bits/stdc++.h>
using namespace std;
#define int long long
#define stoi stoll
using pii=pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
#define all(c) begin(c),end(c)
#define rall(c) rbegin(c),rend(c)
#define fore(x,c) for(auto &&x:c)
#define rep(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define rrep(i, a, n) for(int i=(int)(n-1);i>=a;--i)
#define sz(c) ((int)c.size())
#define contains(c,x) (c.find(x)!=end(c))
#define inseg(l,x,r) ((l)<=(x)&&(x)<(r))
#define dump(...)
#define pb push_back
#define _ 0
const signed INF_=1001001001; const long long INF=1001001001001001001LL;
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) os<<*i<<(i==end(v)-1?"":" ");return os;}
template<class T> istream& operator>>(istream &is,vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) is>>*i;return is;}
template<class T,class U> istream& operator>>(istream &is, pair<T,U> &p) {
    is>>p.first>>p.second;return is;}
template<class T, class U> bool chmax(T &a,const U &b){return a<b?a=b,1:0;}
template<class T, class U> bool chmin(T &a,const U &b){return a>b?a=b,1:0;}
template <class T> void psum(T& c) {partial_sum(begin(c), end(c), begin(c));}
template<class T> using heap=priority_queue<T,vector<T>,greater<T>>;
struct before_main_function {
    before_main_function() {
        cin.tie(nullptr); ios::sync_with_stdio(0);
        cout << setprecision(15) << fixed;
        // #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

template <class Monoid>
class SegmentTree {
    using T = typename Monoid::T;
    int size;
    vector<T> data;
    void build() {
        for (int i = size - 1; i > 0; --i)
            data[i] = Monoid::op(data[i << 1], data[i << 1 | 1]);
    }
public:
    SegmentTree(int n) {
        size = 1;
        while (size < n) size <<= 1;
        data.assign(size << 1, Monoid::identity());
    }
    template <class InputIt>
    SegmentTree(InputIt first, InputIt last) : SegmentTree(std::distance(first, last)){
        copy(first, last, std::begin(data) + size);
        build();
    }

    // 0-indexed
    void update(int p, const T &value) {
        for (data[p += size] = value; p >>= 1; ) data[p] = Monoid::op(data[p << 1], data[p << 1 | 1]);
    }
    // [l, r)  0-indexed
    T query(int l, int r) {
        T resl = Monoid::identity(), resr = Monoid::identity();
        for (l += size, r += size; l < r; l >>= 1, r >>= 1) {
            if (l & 1) resl = Monoid::op(resl, data[l++]);
            if (r & 1) resr = Monoid::op(data[--r], resr);
        }
        return Monoid::op(resl, resr);
    }
    // 0-indexed
    T get(int p) {
        return data[p + size];
    }
};

struct RmQ {
    using T = int;
    static T op(T a, T b) { return min(a, b); }
    static constexpr T identity() { return INF; }
};
struct RMQ {
    using T = int;
    static T op(T a, T b) { return max(a, b); }
    static constexpr T identity() { return -INF; }
};

signed main() {
    int N;
    cin >> N;
    vi P(N);
    cin >> P;
    vi pos(N);
    rep(i, 0, N) {
        pos[P[i] - 1] = i;
    }

    vi L1(N), L2(N), R1(N), R2(N);
    SegmentTree<RMQ> left(N);
    SegmentTree<RmQ> right(N);

    rrep(i, 0, N) {
        int idx = pos[i];
        L1[idx] = left.query(0, idx);
        L2[idx] = left.query(0, L1[idx]);
        R1[idx] = right.query(idx + 1, N);
        R2[idx] = right.query(R1[idx] + 1, N);
        left.update(idx, idx);
        right.update(idx, idx);
    }

    int ans = 0;
    rep(i, 0, N) {
        if (L2[i] == -INF) {
            L2[i] = -1;
        }
        if (R2[i] == INF) {
            R2[i] = N;
        }

        int tmp = 0;
        if (L1[i] != -INF)
            tmp += (L1[i] - L2[i]) * (min(N, R1[i]) - 1 - (i - 1));
        if (R1[i] != INF)
            tmp += (R2[i] - R1[i]) * (i - max(-1LL, L1[i]));
        dump(i, P[i], L2[i], L1[i], R1[i], R2[i], tmp);
        ans += P[i] * tmp;
    }
    cout << ans << endl;
    return (0^_^0);
}



Measured memory_bytes: 9088