from collections import defaultdict, deque, Counter
from heapq import heapify, heappop, heappush
import math
from copy import deepcopy
from itertools import combinations, permutations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right

import sys

def input():
    return sys.stdin.readline().rstrip()
def getN():
    return int(input())
def getNM():
    return map(int, input().split())
def getList():
    return list(map(int, input().split()))
def getListGraph():
    return list(map(lambda x:int(x) - 1, input().split()))
def getArray(intn):
    return [int(input()) for i in range(intn)]

mod = 10 ** 9 + 7
MOD = 998244353
sys.setrecursionlimit(10000000)
inf = float('inf')
eps = 10 ** (-15)
dy = [0, 1, 0, -1]
dx = [1, 0, -1, 0]

#############
# Main Code #
#############

# ここの設定を変えて使う
#####segfunc#####
def segfunc(x, y):
    return max(x, y)
#################

#####ide_ele#####
ide_ele = -inf
#################

class SegTree:
    def __init__(self, init_val, segfunc, ide_ele):
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        # 配列の値を葉にセット
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        # 構築していく
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        k += self.num
        self.tree[k] = x
        while k > 1:
            self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
            k >>= 1

    def query(self, l, r):
        res = self.ide_ele
        l += self.num
        r += self.num
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                res = self.segfunc(res, self.tree[r - 1])
            l >>= 1
            r >>= 1
        return res

"""
パリティ関係ない　とどまれる
max移動するかポイントに移動するか
というかポイントからポイントへの移動方法は限られる

圧縮セグ木か
離れていく方向で見る　右側を見るときと左側を見る時


"""

N = getN()
F = [[0, 0, 0]]
code = set([-inf, 0, inf])
for _ in range(N):
    t, x, v = getNM()
    F.append([x - t, x + t, v])
    code.add(x + t)
code = sorted(list(set(code)))

F.sort(key = lambda i:i[1])
F.sort(key = lambda i:i[0], reverse = True)

d = {}
for i in range(len(code)):
    d[code[i]] = i
seg = SegTree([-inf] * len(code), segfunc, ide_ele) # セグ木立てる
for l, r, v in F:
    # スタート
    if l == r == 0:
        seg.update(d[0], 0)
        continue
    seg.update(d[r], seg.query(0, d[r] + 1) + v)
print(seg.query(0, len(code)))