#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define REP(i,m,n) for(int i=(int)(m); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define RREP(i,m,n) for(int i=(int)(m); i>=(int)(n); i--)
#define rrep(i,n) RREP(i,(n)-1,0)
#define all(v) v.begin(), v.end()
#define endk '\n'
const int inf = 1e9+7;
const ll longinf = 1LL<<60;
const ll mod = 1e9+7;
const ll mod2 = 998244353;
const ld eps = 1e-10;
template<typename T1, typename T2> inline void chmin(T1 &a, T2 b){if(a>b) a=b;}
template<typename T1, typename T2> inline void chmax(T1 &a, T2 b){if(a<b) a=b;}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n; cin >> n;
  vector<ll> A(n); rep(i, n) cin >> A[i];
  int l = 0, r = 2;
  set<pair<ll, int>> st;
  st.insert({A[0], 0});
  st.insert({A[1], 1});
  ll ans = 0;
  while(l < n-1) {
    while(r < n && st.begin()->first + (++st.begin())->first >= st.rbegin()->first) {
      st.insert({A[r], r});
      r++;
    }
    ans += r-l-1-(st.begin()->first + (++st.begin())->first < st.rbegin()->first);
    st.erase({A[l], l});
    l++;
  }
  cout << ans << endk;
  return 0;
}