#include<iostream>
#include<set>
using namespace std;
int N;
int A[2<<17];
bool check(const multiset<int>&S)
{
	return *S.begin()+*next(S.begin())>=*--S.end();
}
main()
{
	cin>>N;
	for(int i=0;i<N;i++)cin>>A[i];
	long ans=0;
	int r=0;
	multiset<int>S;
	for(int i=0;i+1<N;i++)
	{
		while(r<N&&(S.size()<2||check(S)))S.insert(A[r++]);
		if(!check(S))S.erase(S.find(A[--r]));
		ans+=r-i-1;
		S.erase(S.find(A[i]));
	}
	cout<<ans<<endl;
}