package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd:=bf.NewReader(Stdin)
	var n int
	Fscan(rd,&n)
	g := make([][]*Edge, n+1)
	for i := 1; i < n; i++ {
		var u,v,w int
		Fscan(rd,&u,&v,&w)
		g[u] = append(g[u], &Edge{v, w})
		g[v] = append(g[v], &Edge{u, w})
	}
	// ググった結果、自己ループなしの頂点数1個でもパスと呼ぶらしい…知らんがな…
	var ans int
	visited := make([]bool, n+1)
	var dfs func(i int) int
	dfs = func(i int) int {
		visited[i] = true
		weight := 0
		for _, e := range g[i] {
			if visited[e.to] {
				continue
			}
			w := dfs(e.to)+e.weight
			ans = max(ans, weight+w)
			weight = max(weight, w)
		}
		return weight
	}
	dfs(1)
	Println(ans)
}

type Edge struct {
	to, weight int
}