#include <iostream>
#include <vector>
#include <cstring>
using namespace std;
int n;
vector<pair<int, int>> v[10001];
bool vi[10001];
int mp1=0,mp2 = 0;
void chk1(int idx,int pidx) {
	vi[idx] = true;
	for (int i = 0; i < v[idx].size(); i++) {
		if (!vi[v[idx][i].first]) {
			chk1(v[idx][i].first,v[idx][i].second+pidx);
			if (v[idx][i].second + pidx > mp1) {
				mp1 = v[idx][i].second + pidx;
				mp2 = v[idx][i].first;
			}
		}
	}
}
int main() {
	scanf("%d", &n);
	int max_dep = 0;
	for (int i = 0; i < n - 1; i++) {
		int a, b, c;
		scanf("%d%d%d", &a, &b, &c);
		v[a].push_back(make_pair(b, c));
		v[b].push_back(make_pair(a, c));
	}
	chk1(1, 0);
	memset(vi, 0, sizeof(vi));
	chk1(mp2, 0);
	printf("%d\n", mp1);
	return 0;
}