50qiutiao

#include<bits/stdc++.h>
using namespace std;
int n,man[6010],v[6010],fa[6010][2],c,d,ans;
vector<int> a[6010];
void sxdp(int x){
	fa[x][0] = 0,fa[x][1] = man[x];
	for(int i = 0;i < a[x].size();i++){
		int y = a[x][i];
		sxdp(y);
		fa[x][0] += max(fa[y][0],fa[y][1]),fa[x][1] += fa[y][0];
	}
}
int main(){
	cin >> n;
	for (int i = 1;i <= n;i++){
		cin >> c >> d >> man[i];
		a[c].push_back(d);
		v[d] = 1;
	}
	for (int i = 1;i <= n;i++){
		if (!v[i]){
			ans = i;
			break;
		}
	}
	sxdp(ans);
	cout << max(fa[ans][0],fa[ans][1]);
}