// >>> TEMPLATES
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define int ll
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define repR(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep1R(i, n) for (int i = (int)(n); i >= 1; i--)
#define loop(i, a, B) for (int i = a; i B; i++)
#define loopR(i, a, B) for (int i = a; i B; i--)
#define all(x) begin(x), end(x)
#define allR(x) rbegin(x), rend(x)
#define pb push_back
#define eb emplace_back
#define fst first
#define snd second
template <class Int> auto constexpr inf_ = numeric_limits<Int>::max()/2-1;
auto constexpr INF32 = inf_<int32_t>;
auto constexpr INF64 = inf_<int64_t>;
auto constexpr INF   = inf_<int>;
#ifdef LOCAL
#include "debug.hpp"
#else
#define dump(...) (void)(0)
#define say(x) (void)(0)
#define debug if (0)
#endif
template <class T, class Comp> struct pque : priority_queue<T, vector<T>, Comp> { vector<T> &data() { return this->c; } void clear() { this->c.clear(); } };
template <class T> using pque_max = pque<T, less<T>>;
template <class T> using pque_min = pque<T, greater<T>>;
template <class T, class = typename T::iterator, enable_if_t<!is_same<T, string>::value, int> = 0>
ostream& operator<<(ostream& os, T const& a) { bool f = true; for (auto const& x : a) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, size_t N, enable_if_t<!is_same<T, char>::value, int> = 0>
ostream& operator<<(ostream& os, const T (&a)[N]) { bool f = true; for (auto const& x : a) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, class = decltype(begin(declval<T&>())), class = typename enable_if<!is_same<T, string>::value>::type>
istream& operator>>(istream& is, T &a) { for (auto& x : a) is >> x; return is; }
template <class T, class S> ostream& operator<<(ostream& os, pair<T, S> const& p) { return os << p.first << " " << p.second; }
template <class T, class S> istream& operator>>(istream& is, pair<T, S>& p) { return is >> p.first >> p.second; }
struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup;
template <class F> struct FixPoint : private F {
    constexpr FixPoint(F&& f) : F(forward<F>(f)) {}
    template <class... T> constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward<T>(x)...); }
};
struct MakeFixPoint { template <class F> constexpr auto operator|(F&& f) const { return FixPoint<F>(forward<F>(f)); } };
#define MFP MakeFixPoint()|
#define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__)
template <class T, size_t d> struct vec_impl {
    using type = vector<typename vec_impl<T, d-1>::type>;
    template <class... U> static type make_v(size_t n, U&&... x) { return type(n, vec_impl<T, d-1>::make_v(forward<U>(x)...)); }
};
template <class T> struct vec_impl<T, 0> { using type = T; static type make_v(T const& x = {}) { return x; } };
template <class T, size_t d = 1> using vec = typename vec_impl<T, d>::type;
template <class T, size_t d = 1, class... Args> auto make_v(Args&&... args) { return vec_impl<T, d>::make_v(forward<Args>(args)...); }
template <class T> void quit(T const& x) { cout << x << endl; exit(0); }
template <class T, class U> constexpr bool chmin(T& x, U const& y) { if (x > (T)y) { x = (T)y; return true; } return false; }
template <class T, class U> constexpr bool chmax(T& x, U const& y) { if (x < (T)y) { x = (T)y; return true; } return false; }
template <class It> constexpr auto sumof(It b, It e) { return accumulate(b, e, typename iterator_traits<It>::value_type{}); }
template <class T> int sz(T const& x) { return x.size(); }
template <class C, class T> int lbd(C const& v, T const& x) { return lower_bound(begin(v), end(v), x)-begin(v); }
template <class C, class T> int ubd(C const& v, T const& x) { return upper_bound(begin(v), end(v), x)-begin(v); }
constexpr ll mod(ll x, ll m) { assert(m > 0); return (x %= m) < 0 ? x+m : x; }
constexpr ll div_floor(ll x, ll y) { assert(y != 0); return x/y - ((x^y) < 0 and x%y); }
constexpr ll div_ceil(ll x, ll y) { assert(y != 0); return x/y + ((x^y) > 0 and x%y); }
constexpr int dx[] = { 1, 0, -1, 0, 1, -1, -1, 1 };
constexpr int dy[] = { 0, 1, 0, -1, 1, 1, -1, -1 };
constexpr int popcnt(ll x) { return __builtin_popcountll(x); }
mt19937_64 seed_{random_device{}()};
template <class Int> Int rand(Int a, Int b) { return uniform_int_distribution<Int>(a, b)(seed_); }
i64 irand(i64 a, i64 b) { return rand<i64>(a, b); } // [a, b]
u64 urand(u64 a, u64 b) { return rand<u64>(a, b); } //
template <class It> void shuffle(It l, It r) { shuffle(l, r, seed_); }
template <class V> V &operator--(V &v) { for (auto &x : v) --x; return v; }
template <class V> V &operator++(V &v) { for (auto &x : v) ++x; return v; }
bool next_product(vector<int> &v, int m) {
    repR (i, v.size()) if (++v[i] < m) return true; else v[i] = 0;
    return false;
}
bool next_product(vector<int> &v, vector<int> const& s) {
    repR (i, v.size()) if (++v[i] < s[i]) return true; else v[i] = 0;
    return false;
}
template <class vec> int sort_unique(vec &v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
    return v.size();
}
template <class V> auto prefix_sum(V const& a) {
    vector<typename V::value_type> s;
    s.reserve(a.size() + 1);
    s.push_back(0);
    for (auto const& x : a) s.emplace_back(s.back() + x);
    return s;
}
template <class V> auto suffix_sum(V const& a) {
    vector<typename V::value_type> s(a.size() + 1);
    int pos = a.size();
    for (auto it = a.rbegin(); it != a.rend(); ++it, --pos) {
        s[pos-1] = *it + s[pos];
    }
    return s;
}
// <<<
// >>> segment tree 2d (compressed)
template <class Handler, class Int = int> struct Segtree2D : Handler {
    using Value = typename Handler::Value;
    using Handler::unit_value; // () -> Value
    using Handler::merge; // (Value, Value) -> Value

    // >>> internal segtree

    struct segtree { // compressed
        vector<Value> v;
        vector<Int> ys;
        size_t n;
        segtree() = default;
        void add(Int y, Value const& val) {
            size_t i = lower_bound(ys.begin(), ys.end(), y) - ys.begin();
            assert(i < n && ys[i] == y);
            for (i += n; i; i >>= 1) v[i] = merge(v[i], val);
        }
        void set(Int y, Value const& val) {
            size_t i = lower_bound(ys.begin(), ys.end(), y) - ys.begin();
            assert(i < n && ys[i] == y);
            v[i + n] = val;
            i += n;
            while (i > 1) i >>= 1, v[i] = merge(v[i << 1], v[i << 1 | 1]);
        }
        Value get(Int y) const { return get(y, y+1); }
        Value get(Int yl, Int yr) const {
            size_t l = lower_bound(ys.begin(), ys.end(), yl) - ys.begin();
            size_t r = lower_bound(ys.begin(), ys.end(), yr) - ys.begin();
            assert(l <= r);
            Value L = unit_value(), R = unit_value();
            for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
                if (l & 1) L = merge(L, v[l++]);
                if (r & 1) R = merge(v[--r], R);
            }
            return merge(L, R);
        }
    };

    // <<<
    vector<pair<Int, Int>> pos;
    bool built = false;

    vector<segtree> seg;
    size_t n;

    Segtree2D() = default;
    void add_point(Int x, Int y) {
        pos.emplace_back(x, y);
        built = false;
    }
    void build() {
        sort(pos.begin(), pos.end());
        pos.erase(unique(pos.begin(), pos.end()), pos.end());
        n = pos.size();
        seg.resize(n << 1);
        for (size_t i = 0; i < n; ++i) {
            seg[i + n].ys.push_back(pos[i].second);
            seg[i + n].n = 1;
            seg[i + n].v.resize(2, unit_value());
        }
        for (size_t i = n - 1; i; --i) {
            auto const& L = seg[i << 1].ys, R = seg[i << 1 | 1].ys;
            auto &P = seg[i].ys;
            P.resize(L.size() + R.size());
            std::merge(L.begin(), L.end(), R.begin(), R.end(), P.begin());
            P.erase(unique(P.begin(), P.end()), P.end());
            seg[i].n = P.size();
            seg[i].v.resize(P.size() << 1, unit_value());
        }
        built = true;
    }
    size_t x_index(Int x) const {
        auto const minf = numeric_limits<Int>::min();
        return lower_bound(pos.begin(), pos.end(), make_pair(x, minf)) - pos.begin();
    }
    void set(Int x, Int y, Value val) {
        assert(built);
        size_t i = lower_bound(pos.begin(), pos.end(), make_pair(x, y)) - pos.begin();
        assert(i < n && pos[i] == make_pair(x, y));
        seg[i += n].set(y, val);
        while (i > 1) {
            val = merge(val, seg[i ^ 1].get(y));
            seg[i >>= 1].set(y, val);
        }
    }
    void add(Int x, Int y, Value const& val) {
        assert(built);
        size_t i = lower_bound(pos.begin(), pos.end(), make_pair(x, y)) - pos.begin();
        assert(i < n && pos[i] == make_pair(x, y));
        for (i += n; i; i >>= 1) seg[i].add(y, val);
    }
    Value get(Int x, Int y) const { return get(x, x + 1, y, y + 1); }
    Value get(Int xl, Int xr, Int yl, Int yr) const {
        assert(built);
        size_t l = x_index(xl), r = x_index(xr);
        assert(l <= r);
        Value L = unit_value(), R = unit_value();
        for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
            if (l & 1) L = merge(L, seg[l++].get(yl, yr));
            if (r & 1) R = merge(seg[--r].get(yl, yr), R);
        }
        return merge(L, R);
    }
    int size() const { return pos.size(); }
    vector<Value> dat() const {
        assert(built);
        vector<Value> ret;
        for (auto [x, y] : pos) ret.push_back(get(x, y));
        return ret;
    }
};
// <<<

struct Max {
    using Value = int;
    constexpr static Value unit_value() { return -INF; }
    constexpr static Value merge(Value const& x, Value const& y) {
        return max(x, y);
    }
};

int32_t main() {
    int n; cin >> n;
    vector<tuple<int, int, int>> txv;
    Segtree2D<Max> seg;
    seg.add_point(0, 0);
    rep (i, n) {
        int t, x, v; cin >> t >> x >> v;
        txv.eb(t, x, v);
        seg.add_point(t+x, t-x);
    }
    sort(all(txv));
    seg.build();

    seg.set(0, 0, 0);
    int ma = 0;
    for (auto [t, x, v] : txv) {
        int val = seg.get(-INF, t+x+1, -INF, t-x+1) + v;
        seg.set(t+x, t-x, val);
        chmax(ma, val);
    }

    cout << ma << '\n';



}