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*/

#include <bits/stdc++.h>
using namespace std;

using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;
using LL = long long;
using VL = vector<LL>;
using VVL = vector<VL>;
using PLL = pair<LL, LL>;
using VS = vector<string>;

#define ALL(a)  begin((a)),end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define MT make_tuple
#define SZ(a) int((a).size())
#define SORT(c) sort(ALL((c)))
#define RSORT(c) sort(RALL((c)))
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define FF first
#define SS second

template<class S, class T>
istream& operator>>(istream& is, pair<S,T>& p){
  return is >> p.FF >> p.SS;
}
template<class T>
istream& operator>>(istream& is, vector<T>& xs){
  for(auto& x: xs)
	is >> x;
  return is;
}
template<class S, class T>
ostream& operator<<(ostream& os, const pair<S,T>& p){
  return os << p.FF << " " << p.SS;
}
template<class T>
ostream& operator<<(ostream& os, const vector<T>& xs){
  for(unsigned int i=0;i<xs.size();++i)
	os << (i?" ":"") << xs[i];
  return os;
}
template<class T>
void maxi(T& x, T y){
  if(x < y) x = y;
}
template<class T>
void mini(T& x, T y){
  if(x > y) x = y;
}
void debug(istringstream&){}
template <char sep=',', class Head, class... Tail>
void debug(istringstream& iss, Head&& head, Tail&&... tail)
{
  string name;
  getline(iss, name, ',');
  cout << sep << name << "=" << head;
  debug(iss, forward<Tail>(tail)...);
}

#ifdef PYONPOI
#define DEBUG(...) \
  do{ \
    istringstream ss(#__VA_ARGS__); \
    debug<' '>(ss, __VA_ARGS__); \
    cout<<endl; \
  }while(0)
#else
#define DEBUG
#endif


const double EPS = 1e-10;
const double PI  = acos(-1.0);
const LL MOD = 1e9+7;

const int MAX_LOG = 18;
class SparseTable{
private:
  int n;

  // (data, idx)
  using Data = PLL;
  using Data2 = pair<Data,Data>;
  vector<Data2> dat[MAX_LOG];
  vector<int> logTable;
public:
  Data2 top2(const Data2& d1, const Data2& d2) const {
    vector<Data> tmp{d1.FF, d1.SS, d2.FF, d2.SS};
    RSORT(tmp);
    auto res = MP(tmp[0],tmp[1]);
    for(int i=2;res.FF == res.SS;++i) res.SS = tmp[i];
    return res;
  }

  SparseTable(int n, const VL& xs): n(n)
  {
    logTable.resize(n+1);
    logTable[0] = logTable[1] = 0;
    for(int i=2;i<=n;++i)
      logTable[i] = logTable[i>>1] + 1;

    dat[0].resize(n);    
    REP(i,n){
      dat[0][i] = MP(MP(xs[i], i), MP(-1,-1));
    }
    for(int i=1;i<MAX_LOG;++i){
      dat[i].resize(n);
      for(int j=0;j<n;++j){
        auto d1 = dat[i-1][j];
        auto d2 = dat[i-1][min(n-1, j + (1<<(i-1)))];
        dat[i][j] = top2(d1, d2);
      }
    }
  }

  Data2 query(int l, int r) const{
    int d = logTable[r - l];
    return top2(dat[d][l], dat[d][r - (1<<d)]);
  }
};

struct PH{
  template<class T, class U>
  size_t operator()(const pair<T,U>& x) const{
	size_t seed = 0;
	seed ^= hash<T>{}(x.first) + 0x9e3779b9 + (seed<<6) + (seed>>2);
	seed ^= hash<U>{}(x.second) + 0x9e3779b9 + (seed<<6) + (seed>>2);
	return seed;
  }
};

using Memo = unordered_map<PII,LL,PH>;
LL solve(int l, int r, const SparseTable& sp, Memo& memo){
  if(r - l <= 1) return 0;
  if(memo.count(MP(l, r))) return memo[MP(l,r)];

  auto ds = sp.query(l, r);
  auto lval = (ds.FF.SS < ds.SS.SS ? ds.FF : ds.SS);
  auto rval = (ds.FF.SS < ds.SS.SS ? ds.SS : ds.FF);
  auto val = min(ds.FF.FF, ds.SS.FF);

  LL ans = val * (lval.SS - l + 1) * (r - rval.SS);  

  ans += solve(l, rval.SS, sp, memo);
  ans += solve(lval.SS+1, r, sp, memo);
  ans -= solve(lval.SS+1, rval.SS, sp, memo);

  memo[MP(l, r)] = ans;
  return ans;
}

int main(){
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  int N;
  cin >> N;
  VL xs(N);
  cin >> xs;

  Memo memo;
  SparseTable sp(N, xs);
  cout << solve(0, N, sp, memo) << endl;

  return 0;
}

Measured memory_bytes: 78884