#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
typedef long long ll;

#define pb(...) emplace_back(__VA_ARGS__)
#define all(x) x.begin(), x.end()
#define rep(i, n) for (int i = 0; i < (n); i++)

ll f(ll a, ll b) {
    return max(a, b);
}

ll e() {
    return (ll)-1e15;
}

int main() {
    int n;
    cin >> n;
    vector<ll> t(n), x(n), v(n);
    rep(i, n) cin >> t[i] >> x[i] >> v[i];
    vector<ll> a(n), b(n);
    rep(i, n) a[i] = t[i] + x[i], b[i] = t[i] - x[i];
    map<ll, int> ma, mb;
    ma[0] = 1, mb[0] = 1;
    rep(i, n) ma[a[i]] = 1, mb[b[i]] = 1;
    int sz_a = 0, sz_b = 0;
    for (auto &e : ma)
        e.second = sz_a++;
    for (auto &e : mb)
        e.second = sz_b++;
    rep(i, n) a[i] = ma[a[i]], b[i] = mb[b[i]];
    segtree<ll, f, e> seg(sz_b);
    vector<pair<ll, pair<ll, ll>>> vec;
    rep(i, n) if (a[i] >= ma[0]) vec.push_back({a[i], {b[i], v[i]}});
    sort(all(vec));
    seg.set(mb[0], 0);
    ll ans = 0;
    for (auto [p, q] : vec) {
        auto [nb, nv] = q;
        ll val = seg.prod(0, nb + 1) + nv;
        seg.set(nb, max(seg.get(nb), val));
    }
    cout << seg.prod(0, sz_b) << endl;
}