#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)};
}

#line 1 "structure/wavelet/succinct-indexable-dictionary.cpp"

/**
 * @brief Succinct Indexable Dictionary(完備辞書)
 */
struct SuccinctIndexableDictionary {
  size_t length;
  size_t blocks;
  vector< unsigned > bit, sum;

  SuccinctIndexableDictionary() = default;

  SuccinctIndexableDictionary(size_t length) : length(length), blocks((length + 31) >> 5) {
    bit.assign(blocks, 0U);
    sum.assign(blocks, 0U);
  }

  void set(int k) {
    bit[k >> 5] |= 1U << (k & 31);
  }

  void build() {
    sum[0] = 0U;
    for(int i = 1; i < blocks; i++) {
      sum[i] = sum[i - 1] + __builtin_popcount(bit[i - 1]);
    }
  }

  bool operator[](int k) {
    return (bool((bit[k >> 5] >> (k & 31)) & 1));
  }

  int rank(int k) {
    return (sum[k >> 5] + __builtin_popcount(bit[k >> 5] & ((1U << (k & 31)) - 1)));
  }

  int rank(bool val, int k) {
    return (val ? rank(k) : k - rank(k));
  }
};


/**
 * @brief Segment Tree(セグメント木)
 * @docs docs/segment-tree.md
 */
template< typename Monoid >
struct SegmentTree {
  int n, sz;
  vector< Monoid > seg;
  Monoid M1;

  SegmentTree() = default;

  SegmentTree(int n, const Monoid &M1) : n(n), M1(M1) {
    sz = 1;
    while(sz < n) sz <<= 1;
    seg.assign(2 * sz, M1);
  }

  SegmentTree(const vector< Monoid > &v, const Monoid &M1) :
      SegmentTree((int) v.size(), M1) {
    build(v);
  }


  void build(const vector< Monoid > &v) {
    assert(n == (int) v.size());
    for(int k = 0; k < n; k++) seg[k + sz] = v[k];
    for(int k = sz - 1; k > 0; k--) {
      seg[k] = max(seg[2 * k + 0], seg[2 * k + 1]); // 書き方が分かりません...
    }
  }

  void set(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while(k >>= 1) {
      seg[k] = max(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  Monoid get(int k) const {
    return seg[k + sz];
  }

  Monoid operator[](const int &k) const {
    return get(k);
  }

  void apply(int k, const Monoid &x) {
    k += sz;
    seg[k] = max(seg[k], x);
    while(k >>= 1) {
      seg[k] = max(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  Monoid prod(int l, int r) const {
    Monoid L = M1, R = M1;
    for(l += sz, r += sz; l < r; l >>= 1, r >>= 1) {
      if(l & 1) L = max(L, seg[l++]);
      if(r & 1) R = max(seg[--r], R);
    }
    return max(L, R);
  }

  Monoid all_prod() const {
    return seg[1];
  }
};


#line 3 "structure/wavelet/wavelet-matrix-point-add-rectangle-sum.cpp"

/*
 * @brief Wavelet Matrix Point Add Rectangle Sum
 * @docs docs/wavelet-matrix-point-add-rectangle-sum.md
 */
template< typename T, int MAXLOG, typename D >
struct WaveletMatrixPointApplyRectangleProd {
  size_t length;
  SuccinctIndexableDictionary matrix[MAXLOG];

  SegmentTree< D > ds[MAXLOG];
  vector< T > v;
  const D d0;
  int mid[MAXLOG];

  WaveletMatrixPointApplyRectangleProd() = default;

  WaveletMatrixPointApplyRectangleProd(const vector< T > &v, const vector< D > &d, const D &d0)
      : length(v.size()), v(v), d0(d0) {
    assert(v.size() == d.size());
    vector< int > l(length), r(length), ord(length);
    iota(begin(ord), end(ord), 0);
    vector< D > dd(length);
    for(int level = MAXLOG - 1; level >= 0; level--) {
      matrix[level] = SuccinctIndexableDictionary(length + 1);
      int left = 0, right = 0;
      for(int i = 0; i < length; i++) {
        if(((v[ord[i]] >> level) & 1)) {
          matrix[level].set(i);
          r[right++] = ord[i];
        } else {
          l[left++] = ord[i];
        }
      }
      mid[level] = left;
      matrix[level].build();
      ord.swap(l);
      for(int i = 0; i < right; i++) {
        ord[left + i] = r[i];
      }
      for(int i = 0; i < length; i++) {
        dd[i] = d[ord[i]];
      }
      ds[level] = SegmentTree< D >(length, d0);
    }
  }

  pair< int, int > succ(bool f, int l, int r, int level) {
    return {matrix[level].rank(f, l) + mid[level] * f, matrix[level].rank(f, r) + mid[level] * f};
  }

  // count d[i] s.t. (l <= i < r) && (v[i] < upper)
  D rect_max(int l, int r, T upper) {
    D ret = d0;
    for(int level = MAXLOG - 1; level >= 0; level--) {
      if(((upper >> level) & 1)) {
        auto nxt = succ(false, l, r, level);
        ret = max(ret, ds[level].prod(nxt.first, nxt.second));
        l = l - nxt.first + mid[level];
        r = r - nxt.second + mid[level];
      } else {
        tie(l, r) = succ(false, l, r, level);
      }
    }
    return ret;
  }


  void point_add(int k, const D &x) {
    auto &y = v[k];
    for(int level = MAXLOG - 1; level >= 0; level--) {
      bool f = ((y >> level) & 1);
      k = matrix[level].rank(f, k) + mid[level] * f;
      if(ds[level][k] < x) ds[level].apply(k, x);
    }
  }
};

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);
  for(int i = 0; i < (int) ds.size(); i++) {
    auto[t, x, v]=ds[i];
    l.emplace_back(t + x);
    r.emplace_back(t - x);
    m.emplace_back(x, i);
  }
  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());
  vector< int > ldh(ds.size()), rdh(ds.size());
  vector< int64 > dv(ds.size(), -infll);
  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);
    ldh[mdx[i]] = ldx[i];
    rdh[mdx[i]] = rdx[i];
  }
  WaveletMatrixPointApplyRectangleProd< int, 18, int64 > lseg(ldh, dv, -infll);
  WaveletMatrixPointApplyRectangleProd< int, 18, int64 > rseg(rdh, dv, -infll);
  lseg.point_add(mdx[0], 0);
  rseg.point_add(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.rect_max(mdx[i], m.size(), ldx[i] + 1), rseg.rect_max(0, mdx[i], rdx[i] + 1));
    v += v2;
    chmax(ret, v);
    lseg.point_add(mdx[i], v);
    rseg.point_add(mdx[i], v);
  }
  cout << ret << "\n";
}