#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++)
    {
        cin >> a.at(i);
    }
    priority_queue<int> q;
    priority_queue<int, vector<int>, greater<int>> r;
    map<int, int> removed_q, removed_r;
    int bound = 0;
    int64_t ans = 0;
    for (int i = 0; i < n; i++)
    {
        while (bound < n and bound - i < 2)
        {
            q.push(a.at(bound));
            r.push(a.at(bound));
            bound++;
        }
        while (bound <= n)
        {
            while (removed_q[q.top()])
            {
                removed_q[q.top()]--;
                q.pop();
            }
            int mmax = q.top();
            while (removed_r[r.top()])
            {
                removed_r[r.top()]--;
                r.pop();
            }
            int m0 = r.top();
            r.pop();
            while (removed_r[r.top()])
            {
                removed_r[r.top()]--;
                r.pop();
            }
            int m1 = r.top();
            r.push(m0);
            if (mmax > m0 + m1)
            {
                break;
            }
            if (bound < n)
            {
                q.push(a.at(bound));
                r.push(a.at(bound));
            }
            bound++;
        }
        removed_q[a.at(i)]++;
        removed_r[a.at(i)]++;
        ans += max(0, bound - i - 2);
    }
    cout << ans << endl;
    return 0;
}