using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
using System.Threading;
using System.Runtime.CompilerServices;
using System.Diagnostics;
static class Program{
	const int mod=(int)1e9+7;
	static void Main(){
		Sc sc=new Sc();
		var n=sc.I;
		var a=sc.Ia;
		long ans=0;
		St st=new St(a);
		for(int i = 0;i<n-1;i++) {ans+=st.Bsl(i)-i-1;}
		Console.WriteLine("{0}",ans);
	}
}
public class St{
	private const int inf=int.MaxValue>>1;
	public struct Dt{
		public int d1,d2,d3;
		public Dt(bool b){d1=d2=inf;d3=int.MinValue>>1;}
		public Dt(int d1){this.d1=d3=d1;d2=int.MaxValue>>1;}
		public static Dt operator+(Dt a,Dt b){
			a.d2=Max(Min(Min(a.d2,b.d2),a.d1),Min(Min(a.d2,b.d2),b.d1));
			a.d1=Min(a.d1,b.d1);
			a.d3=Max(a.d3,b.d3);
			return a;
		}
		public override string ToString()=>"("+d1.ToString()+" "+d2.ToString()+" "+d3.ToString()+")";
	}
	private Dt[] dat;
	private int n,cnt;
	public St(int[] a){
		n=a.Length;
		cnt=n<<1;
		dat=new Dt[cnt];
		for(int i = n;i<cnt;i++) {dat[i]=new Dt(a[i-n]);}
		for(int i = n-1;i>0;i--) {dat[i]=dat[i<<1]+dat[(i<<1)+1];}
	}
	public void Ud(int q,int b){
		q+=n;
		dat[q].d1=b;
		while(q>1){dat[q>>=1]=dat[q<<1]+dat[(q<<1)+1];}
	}
	public Dt Get(int l,int r){
		Dt x1=new Dt(true),x2=new Dt(true);
		l+=n;r+=n;
		while(l<=r){
			if((l&1)==1){x1+=dat[l++];}
			if((r&1)==0){x2=dat[r--]+x2;}
			l>>=1;r>>=1;
		}
		return x1+x2;
	}
	public int Bsl(int l){
		var x=new Dt(true);
		int r=cnt-1;
		l+=n;
		var sk=new Stack<int>();
		while(l<=r){
			if((l&1)==1){
				var y=x+dat[l];
				if(y.d1+y.d2<y.d3){goto lb;}
				x=y;
				l++;
			}
			if((r&1)==0){sk.Push(r--);}
			l>>=1;r>>=1;
		}
		while(sk.Count>0){
			l=sk.Pop();
			var y=x+dat[l];
			if(y.d1+y.d2<y.d3){goto lb;}
			x=y;
		}
		return n;
		lb:
		while(l<<1<cnt){
			l<<=1;
			var y=x+dat[l];
			if(y.d1+y.d2>=y.d3){x=y;l++;}
		}
		return l-n;
	}
}
public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
	public (T,T) Tp2<T>(){var s=Console.ReadLine().Split();return (Ct<T>(s[0]),Ct<T>(s[1]));}
	public (T,T,T) Tp3<T>(){var s=Console.ReadLine().Split();return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]));}
	public (T1,T1,T2) Tp3<T1,T2>(){var s=Console.ReadLine().Split();return (Ct<T1>(s[0]),Ct<T1>(s[1]),Ct<T2>(s[2]));}
	private T Ct<T>(string s){return (T)Convert.ChangeType(s,typeof(T));}
}