#line 2 "cpplib/util/template.hpp"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")
#include<bits/stdc++.h>
using namespace std;
struct __INIT__{__INIT__(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}}__INIT__;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define endl ('\n')
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>using V=vector<T>;
template<typename T>using VV=V<V<T>>;
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void debug(T t){bool f=0;for(auto i:t){cerr<<(f?" ":"")<<i;f=1;}cerr<<endl;}
template<typename T>inline void debug2(T t){for(auto i:t)output(i);}
#define loop(n) for(long long _=0;_<(long long)(n);++_)
#define _overload4(_1,_2,_3,_4,name,...) name
#define __rep(i,a) repi(i,0,a,1)
#define _rep(i,a,b) repi(i,a,b,1)
#define repi(i,a,b,c) for(long long i=(long long)(a);i<(long long)(b);i+=c)
#define rep(...) _overload4(__VA_ARGS__,repi,_rep,__rep)(__VA_ARGS__)
#define _overload3_rev(_1,_2,_3,name,...) name
#define _rep_rev(i,a) repi_rev(i,0,a)
#define repi_rev(i,a,b) for(long long i=(long long)(b)-1;i>=(long long)(a);--i)
#define rrep(...) _overload3_rev(__VA_ARGS__,repi_rev,_rep_rev)(__VA_ARGS__)

// #define rep(i,...) for(auto i:range(__VA_ARGS__)) 
// #define rrep(i,...) for(auto i:reversed(range(__VA_ARGS__)))
// #define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
// #define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
// #define irep(i) for(lint i=0;;++i)
// inline vector<long long> range(long long n){if(n<=0)return vector<long long>();vector<long long>v(n);iota(v.begin(),v.end(),0LL);return v;}
// inline vector<long long> range(long long a,long long b){if(b<=a)return vector<long long>();vector<long long>v(b-a);iota(v.begin(),v.end(),a);return v;}
// inline vector<long long> range(long long a,long long b,long long c){if((b-a+c-1)/c<=0)return vector<long long>();vector<long long>v((b-a+c-1)/c);for(int i=0;i<(int)v.size();++i)v[i]=i?v[i-1]+c:a;return v;}
// template<typename T>inline T reversed(T v){reverse(v.begin(),v.end());return v;}
#define all(n) begin(n),end(n)
template<typename T,typename E>bool chmin(T& s,const E& t){bool res=s>t;s=min<T>(s,t);return res;}
template<typename T,typename E>bool chmax(T& s,const E& t){bool res=s<t;s=max<T>(s,t);return res;}
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
template<typename T,typename ...Args>auto make_vector(T x,int arg,Args ...args){if constexpr(sizeof...(args)==0)return vector<T>(arg,x);else return vector(arg,make_vector<T>(x,args...));}
#define extrep(v,...) for(auto v:__MAKE_MAT__({__VA_ARGS__}))
#define bit(n,a) ((n>>a)&1)
vector<vector<long long>> __MAKE_MAT__(vector<long long> v){if(v.empty())return vector<vector<long long>>(1,vector<long long>());long long n=v.back();v.pop_back();vector<vector<long long>> ret;vector<vector<long long>> tmp=__MAKE_MAT__(v);for(auto e:tmp)for(long long i=0;i<n;++i){ret.push_back(e);ret.back().push_back(i);}return ret;}
using graph=vector<vector<int>>;
template<typename T>using graph_w=vector<vector<pair<int,T>>>;
template<typename T,typename E>ostream& operator<<(ostream& out,pair<T,E>v){out<<"("<<v.first<<","<<v.second<<")";return out;}
constexpr inline long long powll(long long a,long long b){long long res=1;while(b--)res*=a;return res;}
#line 4 "cpplib/data_structure/disjoint_sparse_table.hpp"

/**
 * @brief DisjointSparseTable
 */

template<typename T,typename F=std::plus<T>>
class disjoint_sparse_table{
	T** table;
	T* data;
	int n=1,cnt=0;
	public:
	F f;
	disjoint_sparse_table(const std::vector<T>& v,F f):f(f){init(v);}
	disjoint_sparse_table(const std::vector<T>& v):f(F()){init(v);}
	void init(const std::vector<T>& v){
		while(n<(int)v.size())n<<=1,cnt++;
		table=new T*[cnt];
		for(int i=0;i<cnt;i++){
			table[i]=new T[n]();
		}
		data =new T[n];
		for(int i=0;i<(int)v.size();i++)data[i]=v[i];
		for(int i=0;i<cnt;i++){
			for(int j=0;j<(n>>(i+1));j++){
				const int mid=(j<<(i+1))+(1<<i);
				for(int k=0;k<(1<<i);k++){
					if(k==0){
						if(0<=mid-1&&mid-1<(int)v.size())table[i][mid-1]=v[mid-1];
						if(0<=mid&&mid<(int)v.size())table[i][mid]=v[mid];
					}
					else{
						if(0<=mid-1-k&&mid-1-k<(int)v.size())table[i][mid-1-k]=f(table[i][mid-k],v[mid-1-k]);
						if(0<=mid+k&&mid+k<(int)v.size())table[i][mid+k]=f(table[i][mid+k-1],v[mid+k]);
					}
				}
			}
		}
	}
	T get(int l,int r){
		if(l==r)return T();
		r--;
		if(l==r)return data[l];
		const int t=31-__builtin_clz((int)(l^r));
		return f(table[t][l],table[t][r]);
	}
};
#line 3 "cpplib/math/binary_search.hpp"
/**
 * @brief 二分探索
 */
template<typename F,typename T=long long>
T bs(T mn,T mx,F func){
    mn--;
    mx++;
	while(mx-mn>1){
		T mid=(mn+mx)/2;
		if(!func(mid))mx=mid;
		else mn=mid;
	}
    return mn;
}
#line 4 "code.cpp"

int main(){
    lint n;
    cin>>n;
    vec a(n),v(n);
    rep(i,n){
        cin>>a[i];
        v[i]=i;
    }
    sort(all(v),[&](auto s,auto t){return a[s]<a[t];});
    set<lint>s;
    vector<lint>l(n),r(n);
    auto f=[](auto s,auto t){return max(s,t);};
    auto g=[](auto s,auto t){return min(s,t);};
    disjoint_sparse_table<lint,decltype(f)>seg(a,f);
    disjoint_sparse_table<lint,decltype(g)>seg2(a,g);
    lint ans=0;
    for(auto i:v){
        auto itr=s.insert(i).first;
        if(itr!=s.begin()){
            l[i]=*prev(itr);
        }else{
            l[i]=-1;
        }
        if(next(itr)!=s.end()){
            r[i]=*next(itr);
        }else{
            r[i]=n;
        }
        if(l[i]!=-1){
            auto k=l[i];
            //a[k]が最小値
            // M<=a[k]+a[i]
            auto aa=(prev(itr)==s.begin()?-1:*prev(itr,2));
            lint p=k-bs(aa+1,k,[&](auto x)->bool{
                return seg.get(x,i+1)>a[k]+a[i];
            });
            lint q=bs(i,r[i]-1,[&](auto x)->bool{
                return seg.get(i,x+1)<=a[k]+a[i];
            })-i+1;
            ans+=p*q;
        }
        if(r[i]!=n){
            auto k=r[i];
            //a[k]が最小値
            // M<=a[k]+a[i]
            auto bb=(next(itr,2)==s.end()?n:*next(itr,2));
            lint p=i-bs(l[i]+1,i,[&](auto x)->bool{
                return seg.get(x,i+1)>a[k]+a[i];
            });
            lint q=bs(k,bb-1,[&](auto x)->bool{
                return seg.get(i,x+1)<=a[k]+a[i];
            })-k+1;
            if(i==2)cerr<<p<<" "<<q<<endl;
            ans+=p*q;
        }
    }
    cout<<ans<<endl;
}