#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int N;
ll A[202020];
int L[202020],R[202020],R2[202020];

template<class V,int NV> class SegTree_Pair {
public:
	vector<pair<V,int> > val;
	static V const def=1<<30;
	pair<V,int> comp(pair<V,int> l,pair<V,int> r){
		int A[4]={l.first,l.second,r.first,r.second};
		sort(A,A+4);
		return {A[0],A[1]};
	}
	SegTree_Pair(){
		val.resize(NV*2);
		int i;
		FOR(i,NV) val[i+NV]=make_pair(def,def);
		for(i=NV-1;i>=1;i--) val[i]=comp(val[2*i],val[2*i+1]);
	};
	pair<V,int> getval(int x,int y,int l=0,int r=NV,int k=1) {
		if(r<=x || y<=l) return make_pair(def,def);
		if(x<=l && r<=y) return val[k];
		return comp(getval(x,y,l,(l+r)/2,k*2),getval(x,y,(l+r)/2,r,k*2+1));
	}
	void update(int entry, V v) {
		entry += NV;
		val[entry]=make_pair(v,def);
		while(entry>1) entry>>=1, val[entry]=comp(val[entry*2],val[entry*2+1]);
	}
};
SegTree_Pair<int,1<<18> st;
template<class V,int NV> class SegTree_2 {
public:
	vector<V> val;
	static V const def=0;
	V comp(V l,V r){ return max(l,r);};
	
	SegTree_2(){val=vector<V>(NV*2,def);};
	V getval(int x,int y,int l=0,int r=NV,int k=1) { // x<=i<y
		if(r<=x || y<=l) return def;
		if(x<=l && r<=y) return val[k];
		return comp(getval(x,y,l,(l+r)/2,k*2),getval(x,y,(l+r)/2,r,k*2+1));
	}
	void update(int entry, V v) {
		entry += NV;
		val[entry]=comp(v,val[entry]); //上書きかチェック
		while(entry>1) entry>>=1, val[entry]=comp(val[entry*2],val[entry*2+1]);
	}
};
SegTree_2<int,1<<18> st2;


void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N) {
		cin>>A[i];
		st.update(i,A[i]);
		st2.update(i,A[i]);
	}
	ll ret=0;
	int L,R;
	FOR(L,N) {
		R=L;
		for(j=18;j>=0;j--) {
			int tmpR=R+(1<<j);
			if(tmpR>=N) continue;
			auto a=st.getval(L,tmpR+1);
			int b=st2.getval(L,tmpR+1);
			if(a.first+a.second>=b) R=tmpR;
		}
		ret+=R-L;
	}
	cout<<ret<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}