//https://vjudge.net/contest/363384#problem/H
/*
* Author : MaxSally
*/
/********   All Required Header Files ********/
#include<bits/stdc++.h>
using namespace std;
/*******  All Required define Pre-Processors and typedef Constants *******/
#define SCD(t) scanf("%d",&t)
#define SCLD(t) scanf("%ld",&t)
#define SCLLD(t) scanf("%lld",&t)
#define SCC(t) scanf("%c",&t)
#define SCS(t) scanf("%s",t)
#define SCF(t) scanf("%f",&t)
#define SCLF(t) scanf("%lf",&t)
#define mem(a, b) memset(a, (b), sizeof(a))
#define rep(i, j, k) for (int i = j ; i <= k ; ++i)
#define rrep(i, j, k) for (int i = j; i >= k; --i)
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define foreach(i, a) for(auto i: a)
#define forEach(it, l) for (auto it = l.begin(); it != l.end(); it++)
#define in(A, B, C) assert( B <= A && A <= C)
#define mp make_pair
#define pb push_back
#define inf (int) (1e9 + 7)
#define epsi 1e-9
#define PI 3.1415926535897932384626433832795
#define mod 1000000007
#define read(type) readInt<type>()
#define io ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define ll long long int
#define left tuyiuoi
#define right fgjhk
#define ss second
#define ff first
#define debug(a) cout << #a << ": " << a << endl
#define debuga1(a, l, r) rep(i, l, r) cout << a[i] << " "; cout << endl
#define Flag(n) cout << "here " << n << endl
const double pi=acos(-1.0);
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef pair<ll, ll> pll;
typedef vector<string> vs;
typedef vector<pii> vii;
typedef vector<pll> vpll;
typedef vector<vi> vvi;
typedef map<int,int> MPII;
typedef set<int> SETI;
typedef multiset<int> MSETI;
typedef long int int32;
typedef unsigned long int uint32;
typedef long long int int64;
typedef unsigned long long int  uint64;

const int N = 100005;
int a[N], n;

struct triad{
    int largest, secondLargest, time;
};

int main(){
    io;
   // freopen("input.txt", "r", stdin);
    cin >> n;
    rep(i, 1, n){
        cin >> a[i];
    }
    stack<triad> s;
    s.push({max(a[n], a[n - 1]), min(a[n], a[n - 1]), 1});
    ll ans = min(a[n], a[n - 1]);
    ll cur = ans;
    rrep(i, n - 2, 1){
        stack<triad> s1;
        s1.push({max(a[i], a[i + 1]), min(a[i], a[i + 1]), 1});
        while(!s.empty() && a[i] > s.top().largest){
            cur -= 1LL * s.top().secondLargest * s.top().time;
            s.top().secondLargest = s.top().largest;
            s.top().largest = a[i];
            cur += 1LL * s.top().secondLargest * s.top().time;
            s1.push(s.top());
            s.pop();
        }
        while(!s.empty() && a[i] > s.top().secondLargest){
            cur -= 1LL * s.top().secondLargest * s.top().time;
            s.top().secondLargest = a[i];
            cur += 1LL * s.top().secondLargest * s.top().time;
            s1.push(s.top());
            s.pop();
        }
        while(!s1.empty()){
            if(!s.empty() && s1.top().largest == s.top().largest && s1.top().secondLargest == s.top().secondLargest){
                s.top().time += s1.top().time;
            }else{
                s.push(s1.top());
            }
            s1.pop();
        }
        cur += s.top().secondLargest;
        ans += cur;
    }
    cout << ans;
    return 0;
}


Measured memory_bytes: 1792