#include<bits/stdc++.h>
using namespace std;
const long long maxn=5e5+5,INF=1e17;
int n;
long long h[maxn];
struct QUJIAN{
	long long l,r;
	QUJIAN friend operator + (QUJIAN x,QUJIAN y)
	{
		return {max(x.l,y.l),min(x.r,y.r)};
	}
};
QUJIAN jiao(QUJIAN x,QUJIAN y)
{
	if (x.l>=x.r-1||y.l>=y.r-1)	return {1,0};
	if (x.r<=y.l+1||y.r<=x.l+1)	return {1,0};
	return {max(x.l,y.l),min(x.r,y.r)};
}
bool check(QUJIAN x){return x.l>x.r;}
QUJIAN st[maxn][21];
int main()
{
	scanf("%d",&n);
	for (int i=1;i<=n;i++)	scanf("%lld",&h[i]);
	for (int i=2;i<n;i++)
	{
		QUJIAN tmp1,tmp2;
		if (h[i-1]<h[i])		tmp1={-INF,h[i-1]+h[i]};
		else if (h[i-1]==h[i])	tmp1={-INF,INF};
		else					tmp1={h[i-1]+h[i],INF};
		
		if (h[i+1]<h[i])		tmp2={-INF,h[i+1]+h[i]};
		else if (h[i+1]==h[i])	tmp2={-INF,INF};
		else					tmp2={h[i+1]+h[i],INF};
//		if (i==3)	cout<<"here:"<<tmp1.l<<" "<<tmp1.r<<endl;
		st[i][0]=jiao(tmp1,tmp2);
		if (st[i][0].l>=st[i][0].r-1)	st[i][0]={-INF,INF};
		else if (st[i][0].l==-INF)		st[i][0]={st[i][0].r,INF};
		else if (st[i][0].r==INF)		st[i][0]={-INF,st[i][0].l};
	}
	for (int j=1;j<=19;j++)
		for (int i=2;i+(1<<j)<=n;i++)	st[i][j]=st[i][j-1]+st[i+(1<<j-1)][j-1];
//	cout<<st[2][0].l<<" "<<st[2][0].r<<endl;
//	cout<<st[3][0].l<<" "<<st[3][0].r<<endl;
	
	long long ans=0;
	for (int i=1;i<n;i++)
	{
		QUJIAN w={-INF,INF};
		int ed=i+1;
		for (int j=19;j>=0;j--)
			if (ed+(1<<j)<=n&&!check(w+st[ed][j]))
			{
				w=w+st[ed][j];
				ed=ed+(1<<j);
			}
//		cout<<i<<" "<<ed<<endl;
		ans+=ed-i;
	}
	printf("%lld",ans);
}