#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define inf INT_MAX
#define fr(i,l,r) for (i=(l); i<=(r); i++)
#define rfr(i,l,r) for (i=(l); i>=(r); i--)
template<typename T>inline void read(T &n){
    T w=1; n=0; char ch=getchar();
    while (!isdigit(ch) && ch!=EOF){ if (ch=='-') w=-1; ch=getchar(); }
    while (isdigit(ch) && ch!=EOF){ n=(n<<3)+(n<<1)+(ch&15); ch=getchar(); }
    n*=w;
}
template<typename T>inline void write(T x){
    if (x==0){ putchar('0'); return ; }
    T tmp;
    if (x>0) tmp=x;
    else tmp=-x;
    if (x<0) putchar('-');
    char F[105];
    long long cnt=0;
    while (tmp){
        F[++cnt]=tmp%10+48;
        tmp/=10;
    }
    while (cnt) putchar(F[cnt--]);
}
#define Min(x,y) x = min(x,y)
#define Max(x,y) x = max(x,y)
//基础配置=================================================================================
const ll N = 500005;
ll n,m,ans=0,x,y,l,r,s,z;
ll h[N];
struct seg{
    ll l,r;
    seg(ll _l=0,ll _r=0){
        l = _l; r = _r; 
    }
};
seg operator + (seg x,seg y){
    Max(x.l,y.l);
    Min(x.r,y.r);
    return x;
}
seg f[N];
struct Uni{
    ll cnt,p[N+N+N+N];
    void clear(){
        cnt = 0;
    }
    void insert(ll x){
        p[++cnt] = x;
    }
    void Unique(){
        if (!cnt) return ;
        sort(p+1,p+1+cnt);
        ll i, len = 1;
        fr(i,2,cnt)
            if (p[i]!=p[len]) p[++len] = p[i];
        cnt = len;
    }
    ll find(ll x){
        ll l = 1, r = cnt, mid;
        while (l<=r){
            mid = (l+r)>>1;
            if (p[mid]==x) return mid;
            if (p[mid]<x) l = mid+1;
            else r = mid-1;
        }
        return -1;
    }
}un;
seg calc(ll x,ll y){//p_i>=p_{i+1}的区间L
    if (x>=y) return seg(-inf,(x+y)/2);
    else return seg((x+y)/2,inf);
}
struct Tree{
    struct node{
        ll l,r;
        ll v,tag;//最小值，覆盖标记
    }t[16*N];
    void build(ll s,ll l,ll r){
        t[s].l = l; t[s].r = r;
        t[s].v = 1; t[s].tag = -1;
        if (l==r) return ;
        ll mid = (l+r)>>1;
        build(s*2,l,mid);
        build(s*2+1,mid+1,r);
    }
    void chg(ll s,ll v){
        t[s].v = t[s].tag = v;
    }
    void down(ll s){
        if (t[s].tag==-1) return ;
        chg(s*2,t[s].tag);
        chg(s*2+1,t[s].tag);
        t[s].tag = -1;
    }
    void change(ll s,ll l,ll r,ll v){
        if (t[s].l>=l && t[s].r<=r){ chg(s,v); return ; }
        down(s);
        if (t[s*2].r>=l) change(s*2,l,r,v);
        if (t[s*2+1].l<=r) change(s*2+1,l,r,v);
        t[s].v = min(t[s*2].v,t[s*2+1].v);
    }
}tr;
int main(){
	// freopen("a.in","r",stdin);
//	freopen(".out","w",stdout);
    ll i,j;
    read(n);
    fr(i,1,n) read(h[i]), h[i]*=2;
    fr(i,2,n) f[i] = calc(h[i],h[i-1]) + calc(h[i],h[i+1]);
    un.clear();
    un.insert(-2*inf); un.insert(2*inf);
    fr(i,2,n) un.insert(f[i].l), un.insert(f[i].r), un.insert(f[i].l+1), un.insert(f[i].r+1);
    // fr(i,2,n) printf("%lld : ban %lld ~ %lld\n",i,f[i].l,f[i].r);
    un.Unique();
    fr(i,2,n)
        f[i].l = un.find(f[i].l),
        f[i].r = un.find(f[i].r);
    // fr(i,2,n) printf("%lld : ban %lld ~ %lld\n",i,f[i].l,f[i].r);
    tr.build(1,1,un.cnt);
    ll ans = 0;
    fr(i,2,n){
        if (f[i].l<=f[i].r) tr.change(1,f[i].l,f[i].r,i);
        ll lf = tr.t[1].v;
        // printf("i = %lld , lf = %lld\n",i,lf);
        ans += i-lf;
    }
    write(ans);
    return 0;
}
//g++ a.cpp -o a -Wall -Wl,--stack=512000000 -std=c++11 -O2