#include<bits/stdc++.h>
using namespace std;
namespace my_std{
	#define ll long long
	#define bl bool
	ll my_pow(ll a,ll b,ll mod){
		ll res=1;
		if(!b) return 1;
		while(b){
			if(b&1) res=(res*a)%mod;
			a=(a*a)%mod;
			b>>=1;
		}
		return res;
	}
	ll qpow(ll a,ll b){
		ll res=1;
		if(!b) return 1;
		while(b){
			if(b&1) res*=a;
			a*=a;
			b>>=1;
		}
		return res;
	}
	#define db double
	#define pf printf
	#define pc putchar
	#define fr(i,x,y) for(register ll i=(x);i<=(y);i++)
	#define pfr(i,x,y) for(register ll i=(x);i>=(y);i--)
	#define go(u) for(ll i=head[u];i;i=e[i].nxt)
	#define enter pc('\n')
	#define space pc(' ')
	#define fir first
	#define sec second
	#define MP make_pair
	#define il inline
	#define inf 8e18
	#define random(x) rand()*rand()%(x)
	#define inv(a,mod) my_pow((a),(mod-2),(mod))
	il ll read(){
		ll sum=0,f=1;
		char ch=0;
		while(!isdigit(ch)){
			if(ch=='-') f=-1;
			ch=getchar();
		}
		while(isdigit(ch)){
			sum=sum*10+(ch^48);
			ch=getchar();
		}
		return sum*f;
	}
	il void write(ll x){
		if(x<0){
			x=-x;
			pc('-');
		}
		if(x>9) write(x/10);
		pc(x%10+'0');
	}
	il void writeln(ll x){
		write(x);
		enter;
	}
	il void writesp(ll x){
		write(x);
		space;
	}
}
using namespace my_std;
set<ll> s1,s2;
vector<ll> vec[1000010];
ll n,a[1000010],lsh[1000010],cnt=0,pre[1000010],suf[1000010],st[1000010],top=0,ans=0;
int main(){
	n=read();
	fr(i,1,n) lsh[++cnt]=a[i]=read();
	sort(lsh+1,lsh+cnt+1);
	cnt=unique(lsh+1,lsh+cnt+1)-lsh-1;
	fr(i,1,n) vec[lower_bound(lsh+1,lsh+cnt+1,a[i])-lsh].push_back(i);
	fr(i,1,cnt) sort(vec[i].begin(),vec[i].end());
	pfr(i,cnt,1){
		pfr(j,(ll)vec[i].size()-1,0){
			ll pos=vec[i][j];
			while(top&&pos<st[top]) top--;
			pre[pos]=st[top];
			st[++top]=pos;
		}
	}
	top=0;
	st[top]=n+1;
	pfr(i,cnt,1){
		fr(j,0,(ll)vec[i].size()-1){
			ll pos=vec[i][j];
			while(top&&pos>st[top]) top--;
			suf[pos]=st[top];
			st[++top]=pos;
		}
	}
	fr(i,1,n) s2.insert(i);
	fr(i,1,cnt){
		fr(j,0,(ll)vec[i].size()-1){
			s1.insert(vec[i][j]);
			s2.erase(vec[i][j]);
		}
		ll l=n+1,r=0;
		if(!s2.empty()){
			l=*s2.begin();
			r=*(--s2.end());
		}
		while(!s1.empty()&&(*s1.begin())<=l) s1.erase(*s1.begin());
		while(!s1.empty()&&(*(--s1.end()))>=r) s1.erase(*(--s1.end()));
		if(s1.empty()) continue;
		l=*s1.begin();
		r=*(--s1.end());
		ll siz=s1.size();
		if(siz==1){
			ans+=(a[pre[l]]+a[suf[l]])*(lsh[i+1]-lsh[i]);
			ans+=(lsh[i]+lsh[i+1]-1)*(lsh[i+1]-lsh[i])/2;
			continue;
		}
		else if((pre[l]+suf[l]+suf[r])<=(pre[l]+pre[r]+suf[r])){
			ans+=(pre[l]+suf[l]+suf[r]+2*siz-3)*(lsh[i+1]-lsh[i]);
			ans+=(3*siz-3)*(lsh[i]+lsh[i+1]-1)*(lsh[i+1]-lsh[i])/2;
		}
		else{
			ans+=(pre[l]+pre[r]+suf[r]+2*siz-3)*(lsh[i+1]-lsh[i]);
			ans+=(3*siz-3)*(lsh[i]+lsh[i+1]-1)*(lsh[i+1]-lsh[i])/2;
		}
	}
	write(ans);
}