#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;

using int64 = long long;
// const int mod = 1e9 + 7;
const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in: v) is >> in;
  return is;
}

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

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

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e: t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}


/**
 * @brief Binary-Indexed-Tree(BIT)
 * @docs docs/binary-indexed-tree.md
 */
struct BinaryIndexedTree {
private:
  vector< int64 > data;

public:
  explicit BinaryIndexedTree(size_t sz) : data(sz + 1, -infll) {}

  void add(int k, const int64 &x) {
    for(++k; k < (int) data.size(); k += k & -k) if(not chmax(data[k], x)) break;
  }

  int64 fold(int r) const {
    int64 ret = -infll;
    for(; r > 0; r -= r & -r) chmax(ret, data[r]);
    return ret;
  }
};

template< typename structure_t, typename get_t, typename update_t, typename merge_f, typename range_get_f, typename update_f >
struct SegmentTree2DCompressed {

  int sz;
  vector< structure_t > seg;
  const merge_f f;
  const range_get_f g;
  const update_f h;
  const get_t identity;
  vector< vector< int > > LL, RR;
  vector< vector< int > > beet;

  SegmentTree2DCompressed(int n, const merge_f &f, const range_get_f &g, const update_f &h, const get_t &identity)
      : f(f), g(g), h(h), identity(identity) {
    sz = 1;
    while(sz < n) sz <<= 1;
    beet.resize(2 * sz);
    LL.resize(2 * sz);
    RR.resize(2 * sz);
  }

  void update(int a, int x, update_t z, int k, int l, int r) {
    if(r <= a || a + 1 <= l) return;
    if(a <= l && r <= a + 1) return h(seg[k], x, z);
    update(a, LL[k][x], z, 2 * k + 0, l, (l + r) >> 1);
    update(a, RR[k][x], z, 2 * k + 1, (l + r) >> 1, r);
    return h(seg[k], x, z);
  }

  void update(int x, int y, update_t z) {
    y = lower_bound(begin(beet[1]), end(beet[1]), y) - begin(beet[1]);
    return update(x, y, z, 1, 0, sz);
  }

  get_t query(int a, int b, int y, int k, int l, int r) {
    if(a >= r || b <= l) return identity;
    if(a <= l && r <= b) return g(seg[k], y);
    return f(query(a, b, LL[k][y], 2 * k + 0, l, (l + r) >> 1),
             query(a, b, RR[k][y], 2 * k + 1, (l + r) >> 1, r));
  }

  get_t query(int a, int b, int y) {
    y = lower_bound(begin(beet[1]), end(beet[1]), y) - begin(beet[1]);
    return query(a, b, y, 1, 0, sz);
  }

  void build() {
    for(int k = (int) beet.size() - 1; k >= sz; k--) {
      sort(begin(beet[k]), end(beet[k]));
      beet[k].erase(unique(begin(beet[k]), end(beet[k])), end(beet[k]));
    }
    for(int k = sz - 1; k > 0; k--) {
      beet[k].resize(beet[2 * k + 0].size() + beet[2 * k + 1].size());
      merge(begin(beet[2 * k + 0]), end(beet[2 * k + 0]), begin(beet[2 * k + 1]), end(beet[2 * k + 1]), begin(beet[k]));
      beet[k].erase(unique(begin(beet[k]), end(beet[k])), end(beet[k]));
      LL[k].resize(beet[k].size() + 1);
      RR[k].resize(beet[k].size() + 1);
      int tail1 = 0, tail2 = 0;
      for(int i = 0; i < beet[k].size(); i++) {
        while(tail1 < beet[2 * k + 0].size() && beet[2 * k + 0][tail1] < beet[k][i]) ++tail1;
        while(tail2 < beet[2 * k + 1].size() && beet[2 * k + 1][tail2] < beet[k][i]) ++tail2;
        LL[k][i] = tail1, RR[k][i] = tail2;
      }
      LL[k][beet[k].size()] = (int) beet[2 * k + 0].size();
      RR[k][beet[k].size()] = (int) beet[2 * k + 1].size();
    }
    for(int k = 0; k < beet.size(); k++) {
      seg.emplace_back(beet[k].size());
    }
  }

  void preupdate(int x, int y) {
    beet[x + sz].push_back(y);
  }
};

int main() {
  int N;
  cin >> N;
  vector< tuple< int, int, int > > ds;
  ds.reserve(N + 1);
  for(int i = 0; i < N; i++) {
    int t, x, v;
    cin >> t >> x >> v;
    ds.emplace_back(t, x, v);
  }
  ds.emplace_back(0, 0, 0);
  sort(begin(ds), end(ds));
  vector< int64 > dp(ds.size(), -infll);
  dp[0] = 0;
  vector< int > l, r, m;
  l.reserve(N + 1);
  r.reserve(N + 1);
  m.reserve(N + 1);
  for(auto&[t, x, v]: ds) {
    l.emplace_back(t + x);
    r.emplace_back(t - x);
    m.emplace_back(x);
  }
  sort(begin(l), end(l));
  l.erase(unique(begin(l), end(l)), end(l));
  sort(begin(r), end(r));
  r.erase(unique(begin(r), end(r)), end(r));
  sort(begin(m), end(m));
  m.erase(unique(begin(m), end(m)), end(m));
  vector< int > ldx(ds.size()), rdx(ds.size()), mdx(ds.size());
  for(int i = 0; i < (int) ds.size(); i++) {
    auto[t, x, v]=ds[i];
    ldx[i] = lower_bound(begin(l), end(l), t + x) - begin(l);
    rdx[i] = lower_bound(begin(r), end(r), t - x) - begin(r);
    mdx[i] = lower_bound(begin(m), end(m), x) - begin(m);
  }
  auto f = [](int64 a, int64 b) { return max(a, b); };
  // みんなの2D segment tree
  using BIT = BinaryIndexedTree;
  auto g = [](BIT &k, int y) { return k.fold(y); };
  auto h = [](BIT &k, int x, int64 y) { k.add(x, y); };

  SegmentTree2DCompressed< BIT, int64, int64, decltype(f), decltype(g), decltype(h) > lseg(m.size(), f, g, h, -infll);
  SegmentTree2DCompressed< BIT, int64, int64, decltype(f), decltype(g), decltype(h) > rseg(m.size(), f, g, h, -infll);
  for(int i = 0; i < (int) ds.size(); i++) {
    lseg.preupdate(mdx[i], ldx[i]);
    rseg.preupdate(mdx[i], rdx[i]);
  }
  lseg.build();
  rseg.build();
  lseg.update(mdx[0], ldx[0], 0);
  rseg.update(mdx[0], rdx[0], 0);
  int64 ret = 0;
  for(int i = 1; i < (int) ds.size(); i++) {
    auto[t2, x2, v2] = ds[i];
    auto v = max(lseg.query(mdx[i], m.size(), ldx[i] + 1), rseg.query(0, mdx[i], rdx[i] + 1));
    v += v2;
    if(v >= 0) {
      chmax(ret, v);
      lseg.update(mdx[i], ldx[i], v);
      rseg.update(mdx[i], rdx[i], v);
    }
  }
  cout << ret << "\n";
}