#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (long long i=0; i<n; i++)
#define pb push_back

long long target;
bool f(long long v) {return v<=target;}

long long op(long long x, long long y) {return max(x, y);}
long long e() {return 0;}

long long ceil_pow2(long long n) {
    long long x = 0;
    while ((1U << x) < (unsigned long long)(n)) x++;
    return x;
}

template <class S, S (*op)(S, S), S (*e)()> struct segtree {
  public:
    segtree() : segtree(0) {}
    segtree(long long n) : segtree(std::vector<S>(n, e())) {}
    segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        for (long long i = 0; i < _n; i++) d[size + i] = v[i];
        for (long long i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(long long p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        d[p] = x;
        for (long long i = 1; i <= log; i++) update(p >> i);
    }

    S get(long long p) {
        assert(0 <= p && p < _n);
        return d[p + size];
    }

    S prod(long long l, long long r) {
        assert(0 <= l && l <= r && r <= _n);
        S sml = e(), smr = e();
        l += size;
        r += size;

        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    template <bool (*f)(S)> long long max_right(long long l) {
        return max_right(l, [](S x) { return f(x); });
    }
    template <class F> long long max_right(long long l, F f) {
        assert(0 <= l && l <= _n);
        assert(f(e()));
        if (l == _n) return _n;
        l += size;
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(op(sm, d[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (f(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*f)(S)> long long min_left(long long r) {
        return min_left(r, [](S x) { return f(x); });
    }
    template <class F> long long min_left(long long r, F f) {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(d[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    long long _n, size, log;
    std::vector<S> d;

    void update(long long k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
};

int main() {
    cin.tie(0); ios::sync_with_stdio(false);
    long long N; cin >> N;
    long long a[N];
    vector<vector<long long>> aidx;
    segtree<long long, op, e> st(N);
    rep(i, N) {
        cin >> a[i];
        aidx.pb({a[i], i});
        st.set(i, a[i]);
    }
    sort(aidx.begin(), aidx.end());
    
    multiset<long long> ms;
    ms.insert(-1); ms.insert(-1);
    ms.insert(N); ms.insert(N);
    long long ans = 0;
    
    rep(i, N) {
        long long idx = aidx[i][1];
        auto itr = ms.lower_bound(idx);
        long long r = *itr;
        long long rr = *++itr;
        itr--; itr--;
        long long l = *itr;
        long long ll = *--itr;
        //cout << idx << endl;
        //cout << ll << " " << l << " " << r << " " << rr << endl;
        if (l!=-1) {
            target = a[l]+a[idx];
            if (st.prod(l, idx+1)<=target) {
                long long max_r = st.max_right<f>(l);
                long long min_l = st.min_left<f>(idx+1);
                ans += (l-max(ll, min_l-1))*(min(r, max_r)-idx);
            }
        }
        
        if (r!=N) {
            target = a[r]+a[idx];
            if (st.prod(idx, r+1)<=target) {
                long long max_r = st.max_right<f>(idx);
                long long min_l = st.min_left<f>(r+1);
                ans += (idx-max(l, min_l-1))*(min(rr, max_r)-r);
            }
        }
        
        ms.insert(idx);
        //cout << ans << endl;
    }
    
    cout << ans << endl;
}