package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
)

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	var n int
	fmt.Fscan(in, &n)
	goods := make([][3]int, n) // time, pos, score
	for i := 0; i < n; i++ {
		fmt.Fscan(in, &goods[i][0], &goods[i][1], &goods[i][2])
	}

	txs := make([][3]int, 0, n)
	set := map[int]struct{}{0: {}} // start pos
	for i := 0; i < n; i++ {
		t, x, s := goods[i][0], goods[i][1], goods[i][2]
		if abs(x) <= t && s > 0 { // reachable
			txs = append(txs, [3]int{t + x, t - x, s})
			set[t-x] = struct{}{}
		}
	}

	sort.Slice(txs, func(i, j int) bool {
		return txs[i][0] < txs[j][0]
	})
	sorted := make([]int, 0, len(set))
	for k := range set {
		sorted = append(sorted, k)
	}
	sort.Ints(sorted)
	mp := make(map[int]int, len(sorted))
	for i, v := range sorted {
		mp[v] = i
	}

	seg := NewSegmentTree(make([]E, len(sorted)))
	for i := 0; i < len(txs); i++ {
		x, s := txs[i][1], txs[i][2]
		pos := mp[x]
		curMax := seg.Query(0, pos+1) + s
		seg.Set(pos, curMax)
	}
	fmt.Fprintln(out, seg.QueryAll())

}

func abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

const INF int = 4e18

// PointSetRangeMax
type E = int

func (*SegmentTree) e() E        { return -INF }
func (*SegmentTree) op(a, b E) E { return max(a, b) }
func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

type SegmentTree struct {
	n, size int
	seg     []E
}

func NewSegmentTree(leaves []E) *SegmentTree {
	res := &SegmentTree{}
	n := len(leaves)
	size := 1
	for size < n {
		size <<= 1
	}
	seg := make([]E, size<<1)
	for i := 0; i < n; i++ {
		seg[i+size] = leaves[i]
	}
	for i := size - 1; i > 0; i-- {
		seg[i] = res.op(seg[i<<1], seg[i<<1|1])
	}
	res.n = n
	res.size = size
	res.seg = seg
	return res
}
func (st *SegmentTree) Get(index int) E {
	if index < 0 || index >= st.n {
		return st.e()
	}
	return st.seg[index+st.size]
}
func (st *SegmentTree) Set(index int, value E) {
	if index < 0 || index >= st.n {
		return
	}
	index += st.size
	st.seg[index] = value
	for index >>= 1; index > 0; index >>= 1 {
		st.seg[index] = st.op(st.seg[index<<1], st.seg[index<<1|1])
	}
}

// [start, end)
func (st *SegmentTree) Query(start, end int) E {
	if start < 0 {
		start = 0
	}
	if end > st.n {
		end = st.n
	}
	if start >= end {
		return st.e()
	}
	leftRes, rightRes := st.e(), st.e()
	start += st.size
	end += st.size
	for start < end {
		if start&1 == 1 {
			leftRes = st.op(leftRes, st.seg[start])
			start++
		}
		if end&1 == 1 {
			end--
			rightRes = st.op(st.seg[end], rightRes)
		}
		start >>= 1
		end >>= 1
	}
	return st.op(leftRes, rightRes)
}
func (st *SegmentTree) QueryAll() E { return st.seg[1] }

// 二分查询最大的 right 使得切片 [left:right] 内的值满足 predicate
func (st *SegmentTree) MaxRight(left int, predicate func(E) bool) int {
	if left == st.n {
		return st.n
	}
	left += st.size
	res := st.e()
	for {
		for left&1 == 0 {
			left >>= 1
		}
		if !predicate(st.op(res, st.seg[left])) {
			for left < st.size {
				left <<= 1
				if predicate(st.op(res, st.seg[left])) {
					res = st.op(res, st.seg[left])
					left++
				}
			}
			return left - st.size
		}
		res = st.op(res, st.seg[left])
		left++
		if (left & -left) == left {
			break
		}
	}
	return st.n
}

// 二分查询最小的 left 使得切片 [left:right] 内的值满足 predicate
func (st *SegmentTree) MinLeft(right int, predicate func(E) bool) int {
	if right == 0 {
		return 0
	}
	right += st.size
	res := st.e()
	for {
		right--
		for right > 1 && right&1 == 1 {
			right >>= 1
		}
		if !predicate(st.op(st.seg[right], res)) {
			for right < st.size {
				right = right<<1 | 1
				if predicate(st.op(st.seg[right], res)) {
					res = st.op(st.seg[right], res)
					right--
				}
			}
			return right + 1 - st.size
		}
		res = st.op(st.seg[right], res)
		if right&-right == right {
			break
		}
	}
	return 0
}