#include <bits/stdc++.h>

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 Abstract Binary Indexed Tree(抽象化BIT)
 * @docs docs/abstract-binary-indexed-tree.md
 */
template< typename T, typename F >
struct AbstractBinaryIndexedTree {
private:
  int n;
  vector< T > data;
  const F f;
  const T e;

public:
  AbstractBinaryIndexedTree() = default;

  explicit AbstractBinaryIndexedTree(int n, const F f, const T &e) : n(n), f(f), e(e) {
    data.assign(n + 1, e);
  }

  explicit AbstractBinaryIndexedTree(const vector< T > &v, const F f, const T &e) :
      AbstractBinaryIndexedTree((int) v.size(), f, e) {
    build(v);
  }

  void build(const vector< T > &v) {
    assert(n == (int) v.size());
    for(int i = 1; i <= n; i++) data[i] = v[i - 1];
    for(int i = 1; i <= n; i++) {
      int j = i + (i & -i);
      if(j <= n) data[j] = f(data[j], data[i]);
    }
  }

  void apply(int k, const T &x) {
    for(++k; k <= n; k += k & -k) data[k] = f(data[k], x);
  }

  T prod(int r) const {
    T ret{e};
    for(; r > 0; r -= r & -r) ret = f(ret, data[r]);
    return ret;
  }
};

template< typename T, typename F >
AbstractBinaryIndexedTree< T, F > get_abstract_binary_indexed_tree(int n, const F &f, const T &e) {
  return AbstractBinaryIndexedTree{n, f, e};
}

template< typename T, typename F >
AbstractBinaryIndexedTree< T, F > get_abstract_binary_indexed_tree(const vector< T > &v, const F &f, const T &e) {
  return AbstractBinaryIndexedTree{v, f, e};
}

/**
 * @brief Abstract 2D Binary Indexed Tree Compressed(抽象化2次元座圧BIT)
 */
template< typename T, typename F >
struct Abstract2DBinaryIndexedTreeCompressed {
private:
  int n;
  vector< AbstractBinaryIndexedTree< T, F > > data;
  const F f;
  const T e;
  vector< int > hs;
  vector< vector< int > > beet;
  vector< vector< int > > pos;
public:
  Abstract2DBinaryIndexedTreeCompressed(const vector< int > &hs, const F f, const T &e) :
      n((int) hs.size()), hs(hs), f(f), e(e) {
    vector< int > ord(n);
    iota(begin(ord), end(ord), 0);
    sort(begin(ord), end(ord), [&](int a, int b) {
      return hs[a] < hs[b];
    });
    beet.resize(n + 1);
    for(auto &&i: ord) {
      for(int k = i + 1; k <= n; k += k & -k) {
        beet[k].emplace_back(hs[i]);
      }
    }
    data.reserve(n + 1);
    pos.resize(n + 1);
    for(int k = 0; k <= n; k++) {
      beet[k].erase(unique(begin(beet[k]), end(beet[k])), end(beet[k]));
      data.emplace_back((int) beet[k].size(), f, e);
      pos[k].resize(beet[k].size());
    }
    for(int k = n; k > 0; k--) {
      int p = k + (k & -k);
      if(p <= n) {
        int tail = 0;
        for(int i = 0; i < beet[k].size(); i++) {
          while(tail < (int) beet[p].size() and beet[p][tail] < beet[k][i]) {
            ++tail;
          }
          pos[k][i] = tail;
        }
      }
    }
  }

  void apply(int k1, const T &x) {
    int k2 = hs[k1];
    int p = lower_bound(begin(beet[k1 + 1]), end(beet[k1 + 1]), k2) - begin(beet[k1 + 1]);
    for(++k1; k1 <= n; p = pos[k1][p], k1 += k1 & -k1) {
      data[k1].apply(p, x);
    }
  }

  T prod(int r1, int r2) const {
    T ret{e};
    for(; r1 > 0; r1 -= r1 & -r1) {
      int p = lower_bound(begin(beet[r1]), end(beet[r1]), r2) - begin(beet[r1]);
      ret = f(ret, data[r1].prod(p));
    }
    return ret;
  }
};

template< typename T, typename F >
Abstract2DBinaryIndexedTreeCompressed< T, F > get_abstract_2d_binary_indexed_tree_compressed(const vector< int > &hs, const F &f, const T &e) {
  return Abstract2DBinaryIndexedTreeCompressed{hs, f, e};
}

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;
  vector< pair< int, int > > m;
  l.reserve(N + 1);
  r.reserve(N + 1);
  m.reserve(N + 1);
  int ptr = 0;
  for(auto&[t, x, v]: ds) {
    l.emplace_back(t + x);
    r.emplace_back(t - x);
    m.emplace_back(x, ptr++);
  }
  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));
  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), make_pair(x, i)) - begin(m);
  }
  auto f = [](int64 a, int64 b) { return max(a, b); };
  // みんなの2D segment tree

  vector< int > ladx(m.size()), radx(m.size());
  for(int i = 0; i < (int) ds.size(); i++) {
    ladx[m.size() - mdx[i] - 1] = ldx[i];
    radx[mdx[i]] = rdx[i];
  }
  auto lseg = get_abstract_2d_binary_indexed_tree_compressed(ladx, f, -infll);
  auto rseg = get_abstract_2d_binary_indexed_tree_compressed(radx, f, -infll);
  vector< int > ord(ds.size());
  lseg.apply(m.size() - mdx[0] - 1, 0);
  rseg.apply(mdx[0], 0);
  int64 ret = 0;
  for(int i = 1; i < (int) ds.size(); i++) {
    auto[t2, x2, v2] = ds[i];
    auto v = max(lseg.prod(m.size() - mdx[i], ldx[i] + 1), rseg.prod(mdx[i], rdx[i] + 1));
    v += v2;
    if(v >= 0) {
      chmax(ret, v);
      lseg.apply(m.size() - mdx[i] - 1, v);
      rseg.apply(mdx[i], v);
    }
  }
  cout << ret << "\n";
}