#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

int main(){
    int N; cin >> N;

    vector<int> a(N);
    rep(i, N) cin >> a[i];

    multiset<int> s;

    ll ans = 0;

    int ptr = 0;

    rep(i, N){
        while(ptr < N){
            s.emplace(a[ptr]);
            if(sz(s) >= 2){
                auto it = s.begin();
                int A = *it, B = *(++it), C = *s.rbegin();
                if(A+B < C) {s.erase(s.find(a[ptr])); break;}
            }
            ptr++;
        }

        s.erase(s.find(a[i]));

        ans += max(0, ptr-(i+1));
    }

    cout << ans << '\n';
}