#include 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; using pil = pair; using pli = pair; using pll = pair; const int MOD = 1000000007; //const int MOD = 998244353; const int inf = (1<<30)-1; const ll INF = (1LL<<60)-1; template bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;}; template 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 a(N); rep(i, N) cin >> a[i]; multiset 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'; }