#define LOCAL
#include <bits/stdc++.h>
using namespace std;
#pragma region Macros
typedef long long ll;
typedef __int128_t i128;
typedef unsigned int uint;
typedef unsigned long long ull;
#define ALL(x) (x).begin(), (x).end()

template <typename T> istream& operator>>(istream& is, vector<T>& v) {
    for (T& x : v) is >> x;
    return is;
}
template <typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
    for (size_t i = 0; i < v.size(); i++) {
        os << v[i] << (i + 1 == v.size() ? "" : " ");
    }
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& m) {
    os << '{';
    for (auto itr = m.begin(); itr != m.end();) {
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr != m.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const unordered_map<T, U>& m) {
    os << '{';
    for (auto itr = m.begin(); itr != m.end();) {
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr != m.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const set<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const multiset<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const deque<T>& v) {
    for (size_t i = 0; i < v.size(); i++) {
        os << v[i] << (i + 1 == v.size() ? "" : " ");
    }
    return os;
}
template <typename T, size_t N> ostream& operator<<(ostream& os, const array<T, N>& v) {
    for (size_t i = 0; i < N; i++) {
        os << v[i] << (i + 1 == N ? "" : " ");
    }
    return os;
}

template <int i, typename T> void print_tuple(ostream&, const T&) {}
template <int i, typename T, typename H, class... Args> void print_tuple(ostream& os, const T& t) {
    if (i) os << ',';
    os << get<i>(t);
    print_tuple<i + 1, T, Args...>(os, t);
}
template <typename... Args> ostream& operator<<(ostream& os, const tuple<Args...>& t) {
    os << '{';
    print_tuple<0, tuple<Args...>, Args...>(os, t);
    return os << '}';
}

void debug_out() { cerr << '\n'; }
template <class Head, class... Tail> void debug_out(Head&& head, Tail&&... tail) {
    cerr << head;
    if (sizeof...(Tail) > 0) cerr << ", ";
    debug_out(move(tail)...);
}
#ifdef LOCAL
#define debug(...)                                                                   \
    cerr << " ";                                                                     \
    cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n'; \
    cerr << " ";                                                                     \
    debug_out(__VA_ARGS__)
#else
#define debug(...) void(0)
#endif

template <typename T> T gcd(T x, T y) { return y != 0 ? gcd(y, x % y) : x; }
template <typename T> T lcm(T x, T y) { return x / gcd(x, y) * y; }

int topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }
int topbit(long long t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }
int botbit(signed a) { return a == 0 ? 32 : __builtin_ctz(a); }
int botbit(long long a) { return a == 0 ? 64 : __builtin_ctzll(a); }
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(long long t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
long long MSK(int n) { return (1LL << n) - 1; }

template <class T> T ceil(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? (x + y - 1) / y : x / y);
}
template <class T> T floor(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? x / y : (x - y + 1) / y);
}

template <class T1, class T2> inline bool chmin(T1& a, T2 b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template <class T1, class T2> inline bool chmax(T1& a, T2 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <typename T> void mkuni(vector<T>& v) {
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
}
template <typename T> int lwb(const vector<T>& v, const T& x) { return lower_bound(v.begin(), v.end(), x) - v.begin(); }
#pragma endregion

#include "atcoder/segtree"

#include <algorithm>
#include <cassert>
#include <functional>
#include <vector>

template <typename structure_t, typename value_t, typename coordinate_t> struct RangeTree {
private:
    using structure_new = std::function<structure_t*(int)>;
    using structure_set = std::function<void(structure_t&, int, value_t)>;
    using structure_prod = std::function<value_t(structure_t&, int, int)>;
    using value_merge = std::function<value_t(value_t, value_t)>;
    using Pt = std::pair<coordinate_t, coordinate_t>;

public:
    RangeTree(const structure_new& st_new,
              const structure_set& st_set,
              const structure_prod& st_prod,
              const value_merge& op,
              const value_t& e)
        : st_new(st_new), st_set(st_set), st_prod(st_prod), op(op), e(e) {}

    void add_point(coordinate_t x, coordinate_t y) { points.emplace_back(x, y); }

    void build() {
        std::sort(points.begin(), points.end());
        points.erase(std::unique(points.begin(), points.end()), points.end());
        n = points.size();
        yxs.resize(n << 1);
        segs.resize(n << 1, nullptr);
        for (int i = 0; i < n; i++) yxs[n + i] = {{points[i].second, points[i].first}};
        for (int i = n - 1; i >= 0; i--) {
            auto& lch = yxs[i << 1 | 0];
            auto& rch = yxs[i << 1 | 1];
            std::merge(lch.begin(), lch.end(), rch.begin(), rch.end(), std::back_inserter(yxs[i]));
            yxs[i].erase(std::unique(yxs[i].begin(), yxs[i].end()), yxs[i].end());
        }
        for (int i = 0; i < (n << 1); i++) segs[i] = st_new(yxs[i].size());
    }

    void set(coordinate_t x, coordinate_t y, value_t val) {
        int i = std::distance(points.begin(), std::lower_bound(points.begin(), points.end(), std::make_pair(x, y)));
        assert(i < n && points[i] == std::make_pair(x, y));
        for (i += n; i; i >>= 1) st_set(*segs[i], zip(i, x, y), val);
    }

    value_t prod(coordinate_t xl, coordinate_t xr, coordinate_t yl, coordinate_t yr) {
        assert(xl <= xr && yl <= yr);
        value_t L = e, R = e;
        int l = zip(xl), r = zip(xr);
        for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
            if (l & 1) L = op(L, st_prod(*segs[l], zip(l, yl), zip(l, yr))), l++;
            if (r & 1) --r, R = op(st_prod(*segs[r], zip(r, yl), zip(r, yr)), R);
        }
        return op(L, R);
    }

private:
    int n;
    const structure_new st_new;
    const structure_set st_set;
    const structure_prod st_prod;
    const value_merge op;
    const value_t e;
    std::vector<Pt> points;
    std::vector<std::vector<Pt>> yxs;
    std::vector<structure_t*> segs;

    int zip(coordinate_t x) {
        auto compare = [](const Pt& l, const Pt& r) { return l.first < r.first; };
        return std::distance(
            points.begin(), std::lower_bound(points.begin(), points.end(), std::make_pair(x, coordinate_t()), compare));
    }

    int zip(int i, coordinate_t y) {
        auto compare = [](const Pt& l, const Pt& r) { return l.first < r.first; };
        return std::distance(
            yxs[i].begin(), std::lower_bound(yxs[i].begin(), yxs[i].end(), std::make_pair(y, coordinate_t()), compare));
    }

    int zip(int i, coordinate_t x, coordinate_t y) {
        return std::distance(yxs[i].begin(), std::lower_bound(yxs[i].begin(), yxs[i].end(), std::make_pair(y, x)));
    }
};

const int INF = 1e9;
const long long IINF = 1e18;
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const char dir[4] = {'D', 'R', 'U', 'L'};
const long long MOD = 1000000007;
// const long long MOD = 998244353;

ll op(ll l, ll r) { return max(l, r); }

ll e() { return -IINF; }

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    struct fruit {
        int T, X, V;
        fruit(int T, int X, int V) : T(T), X(X), V(V) {}
        bool operator<(const fruit& f) const { return T < f.T; }
    };
    vector<fruit> fs;
    for (int i = 0; i < N; i++) {
        int T, X, V;
        cin >> T >> X >> V;
        fs.emplace_back(T, X, V);
    }

    sort(fs.begin(), fs.end());
    auto f = [](ll l, ll r) { return max(l, r); };
    using SEG = atcoder::segtree<ll, op, e>;
    auto st_new = [](int n) { return new SEG(n); };
    auto st_set = [](SEG& SEG, int i, ll x) { SEG.set(i, x); };
    auto st_prod = [](SEG& SEG, int l, int r) { return SEG.prod(l, r); };
    RangeTree<SEG, ll, int> RT(st_new, st_set, st_prod, f, -IINF);
    RT.add_point(0, 0);
    for (auto& p : fs) {
        int T = p.T, X = p.X;
        RT.add_point(T - X, T + X);
    }
    RT.build();
    RT.set(0, 0, 0);
    ll ans = 0;

    for (auto& p : fs) {
        int T = p.T, X = p.X, V = p.V;
        ll val = RT.prod(-INF * 2, T - X + 1, -INF * 2, T + X + 1) + V;
        chmax(ans, val);
        RT.set(T - X, T + X, val);
    }

    cout << ans << '\n';
    return 0;
}