// Om Namah Shivaya
// GM in 121 days
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}
void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
template<typename T> void amin(T &a, T b) { a = min(a, b); }
template<typename T> void amax(T &a, T b) { a = max(a, b); }
void usaco(string filename) {
freopen((filename + ".in").c_str(), "r", stdin);
freopen((filename + ".out").c_str(), "w", stdout);
}
const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;
#include "dreaming.h"
vector<pii> adj[maxn];
int dp1[maxn], dp2[maxn];
multiset<int> ms1[maxn], ms2[maxn];
vector<bool> vis(maxn);
int mn = inf1, best = -1;
int mxval = -1, mxnode = -1;
void dfs1(int node, int par) {
ms1[node].insert(0);
vis[node] = 1;
for (auto [child, w] : adj[node]) {
if (child == par) conts;
dfs1(child, node);
ms1[node].insert(dp1[child] + w);
if (sz(ms1[node]) > 2) ms1[node].erase(ms1[node].begin());
}
dp1[node] = *ms1[node].rbegin();
dp2[node] = dp1[node];
ms2[node] = ms1[node];
}
void dfs2(int node, int par) {
for (auto [child, w] : adj[node]) {
if (child == par) conts;
ll temp = dp1[child] + w;
auto it = ms2[node].find(temp);
if (it != ms2[node].end()) {
ms2[node].erase(it);
}
ms2[child].insert(*ms2[node].rbegin() + w);
if (sz(ms2[child]) > 2) {
ms2[child].erase(ms2[child].begin());
}
dp2[child] = *ms2[child].rbegin();
dfs2(child, node);
ms2[node].insert(temp);
if (sz(ms2[node]) > 2) {
ms2[node].erase(ms2[node].begin());
}
}
}
void dfs3(int node, int par) {
if (dp2[node] < mn) {
mn = dp2[node];
best = node;
}
vis[node] = 1;
for (auto [child, w] : adj[node]) {
if (child == par) conts;
dfs3(child, node);
}
}
void dfs4(int node, int par, int sum) {
if (sum > mxval) {
mxval = sum;
mxnode = node;
}
for (auto [child, w] : adj[node]) {
if (child == par) conts;
dfs4(child, node, sum + w);
}
}
int travelTime(int n, int m, int l, int a[], int b[], int t[]) {
// https://www.quora.com/What-is-the-solution-for-Dreaming-on-IOI-2013
rep(i, m) {
int u = a[i], v = b[i], w = t[i];
adj[u].pb({v, w});
adj[v].pb({u, w});
}
rep(i, n) {
if (vis[i]) conts;
dfs1(i, -1);
dfs2(i, -1);
}
rep(i, n) vis[i] = 0;
vector<pii> vals;
rep(i, n) {
if (vis[i]) conts;
mn = inf1, best = -1;
dfs3(i, -1);
vals.pb({mn, best});
}
sort(rall(vals));
int siz = sz(vals);
rep1(i, siz - 1) {
int u = vals[0].ss, v = vals[i].ss;
adj[u].pb({v, l}), adj[v].pb({u, l});
}
dfs4(0, -1, 0);
dfs4(mxnode, -1, 0);
return mxval;
}
