import sys
#input = sys.stdin.readline #文字列につけてはダメ
input = sys.stdin.buffer.readline #文字列につけてはダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]

class SegmentTree(object):
    def __init__(self, A, dot, unit):
        n = 1 << (len(A) - 1).bit_length()
        tree = [unit] * (2 * n)
        for i, v in enumerate(A):
            tree[i + n] = v
        for i in range(n - 1, 0, -1):
            tree[i] = dot(tree[i << 1], tree[i << 1 | 1])
        self._n = n
        self._tree = tree
        self._dot = dot
        self._unit = unit

    def __getitem__(self, i):
        return self._tree[i + self._n]

    def update(self, i, v):
        i += self._n
        self._tree[i] = v
        while i != 1:
            i >>= 1
            self._tree[i] = self._dot(self._tree[i << 1], self._tree[i << 1 | 1])

    def add(self, i, v):
        self.update(i, self[i] + v)

    def sum(self, l, r): #これで[l,r)から取り出す。
        l += self._n
        r += self._n
        l_val = r_val = self._unit
        while l < r:
            if l & 1:
                l_val = self._dot(l_val, self._tree[l])
                l += 1
            if r & 1:
                r -= 1
                r_val = self._dot(self._tree[r], r_val)
            l >>= 1
            r >>= 1
        return self._dot(l_val, r_val)


def compress(S):
    S = set(S); S = list(S)
    S.sort()
    dic_comp_ori = {}
    dic_ori_comp = {}
    for i,a in enumerate(S):
        dic_ori_comp[a] = i
        dic_comp_ori[i] = a
    return dic_comp_ori, dic_ori_comp 

def main():
    N = int(input()); INF = pow(10,18)
    Z = [(0,0,0)]; A = [0]; B = [0] #スタート地点
    for i in range(N):
        t,x,v = map(int,input().split())
        a = t+x
        b = t-x
        Z.append((a,b,v))
        A.append(a)
        B.append(b)
    Z.sort(key = lambda x: (x[0],x[1]))
    #print(Z)
    dica_comp_ori, dica_ori_comp = compress(A)
    dicb_comp_ori, dicb_ori_comp = compress(B)
    dp = SegmentTree([-INF]*(N+1), max, -INF)
    Flag = True
    for a,b,v in Z:
        if Flag:
            if v == 0:
                b0 = dicb_ori_comp[0]
                dp.update(b0,0) #スタート地点に来たので初期化
                Flag = False
            continue
        bi = dicb_ori_comp[b]
        nv = dp.sum(0,bi+1) + v
        #print(nv)
        dp.update(bi,nv)
    ans = dp.sum(0,N+1)
    print(ans)



if __name__ == '__main__':
    main()