#include <atcoder/segtree>
#include <algorithm>
#include <iostream>
#include <map>
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<P, ll> PP;

const ll INF = 1000000000000000;

struct S{
    ll x;
};

S mx(S a, S b){
    return S{max(a.x, b.x)};
}

S e(){
    return S{-INF};
}

ll l[200005], r[200005];
ll v[200005];
ll dp[200005];
P pl[200005], pr[200005];
int re[200005];

void divide_conquer(int a, int b){
	if(b - a <= 1){
		for(int i = a; i < b; i++){
			for(int j = a; j < i; j++){
				if(l[i] <= l[j] && r[i] >= r[j]) dp[i] = max(dp[i], dp[j] + v[i]);
			}
		}
		return;
	}
    divide_conquer(a, (a + b) / 2);
	int m = b - a;
	for(int i = a; i < b; i++){
		pl[i - a] = P(l[i], i);
		pr[i - a] = P(r[i], i);
	}
	sort(pl, pl + m);
	sort(pr, pr + m);
	for(int i = 0; i < m; i++) re[pl[i].second] = i;
	segtree<S, mx, e> seg(m);
	for(int e = 0; e < m; e++){
		int i = pr[e].second;
		if(i < (a + b) / 2) seg.set(re[i], S{dp[i]});
		else dp[i] = max(dp[i], seg.prod(re[i], m).x + v[i]);
	}
    divide_conquer((a + b) / 2, b);
}

int main()
{
    int n;
	cin >> n;
	PP q[200005];
	q[0] = PP(P(0, 0), 0);
	for(int i = 1; i <= n; i++){
		ll t, x, v;
		cin >> t >> x >> v;
		q[i] = PP(P(t, x), v);
	}
	sort(q, q + n + 1);
	for(int i = 0; i <= n; i++){
		v[i] = q[i].second;
		l[i] = q[i].first.second - q[i].first.first;
		r[i] = q[i].first.second + q[i].first.first;
		dp[i] = -INF;
	}
	dp[0] = 0;
	if(n <= 5000){
		for(int i = 1; i <= n; i++){
			for(int j = 0; j < i; j++){
				if(l[i] <= l[j] && r[i] >= r[j]) dp[i] = max(dp[i], dp[j] + v[i]);
			}
		}
	}
	else{
		divide_conquer(0, n + 1);
	}
	ll ans = 0;
	for(int i = 1; i <= n; i++) ans = max(ans, dp[i]);
    cout << ans << endl;
}