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#include <bits/stdc++.h>
using namespace std;
const int N = 10010, M = N << 1;
//  暴力搜索,从每个节点为根出发,遍历整根树,找出距离自己的最大距离,然后每个最大距离取min
// 11/17,其它TLE,无法AC
int n;
int ans; // 树的直径
// 邻接表
int e[M], h[N], idx, w[M], ne[M];
void add(int a, int b, int c = 0) {
e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++;
}
void dfs(int u, int fa, int sum) {
if (sum > ans) ans = sum;
for (int i = h[u]; ~i; i = ne[i]) {
int v = e[i];
if (v == fa) continue; // 不走回头路
dfs(v, u, sum + w[i]);
}
}
int main() {
// 初始化邻接表
memset(h, -1, sizeof h);
cin >> n;
for (int i = 1; i < n; i++) { // n-1条边
int a, b, c;
cin >> a >> b >> c;
add(a, b, c), add(b, a, c); // 无向图
}
// 多次dfs,是TLE的罪魁祸首
for (int i = 1; i <= n; i++) dfs(i, 0, 0);
// 输出结果
printf("%d", ans);
return 0;
}