N = int(input())
dat = []
s = set()
for _ in range(N):
    t,x,v = map(int,input().split())
    if t < abs(x):continue
    dat.append((t-x,t,x,v))
    s.add(x+t)
s.add(0)

inf = -10 ** 18
D = {v:i for i,v in enumerate(sorted(s))}
n = len(D)
bit = [inf] * (n+1)
def add(i,x):
    while i <= n:
        bit[i] = max(bit[i],x)
        i += i & -i
def getmax(i):
    ans = 0
    while i > 0:
        ans = max(ans,bit[i])
        i -= i & -i
    return ans

dat.sort(key = lambda x:x[0])
add(D[0] + 1,0)
for d,t,x,v in dat:
    a = D[x + t] + 1
    b = getmax(a)
    tmp = b + v
    add(a,tmp)
ans = getmax(n)
if ans < 0:
    ans = 0
print(ans)