#include <bits/stdc++.h>
using namespace std;
vector<vector<pair<int, int>>> connections(100000);
vector<bool> visited(100000);
vector<pair<int, int>> far(100000, {-1, 0});
vector<pair<int, int>> sfar(100000, {-1, 0});
int treeans;
int treedia;
vector<int> answers;
vector<int> dias;
void fdfs(int cur, int par) {
visited[cur] = true;
for (pair<int, int> next: connections[cur]) {
if (next.first == par) continue;
fdfs(next.first, cur);
int d = far[next.first].second + next.second;
if (d > far[cur].second) {
sfar[cur] = far[cur];
far[cur].first = next.first;
far[cur].second = d;
} else if (d > sfar[cur].second) {
sfar[cur].first = next.first;
sfar[cur].second = d;
}
}
}
void sdfs(int cur, int par) {
for (pair<int, int> next: connections[cur]) {
if (next.first == par) continue;
if (far[cur].first != next.first) {
if (far[cur].second + next.second > far[next.first].second) {
sfar[next.first] = far[next.first];
far[next.first] = {cur, far[cur].second + next.second};
} else if (far[cur].second + next.second > sfar[next.first].second) {
sfar[next.first] = {cur, far[cur].second + next.second};
}
} else {
if (sfar[cur].second + next.second > far[next.first].second) {
sfar[next.first] = far[next.first];
far[next.first] = {cur, sfar[cur].second + next.second};
} else if (far[cur].second + next.second > sfar[next.first].second) {
sfar[next.first] = {cur, sfar[cur].second + next.second};
}
}
sdfs(next.first, cur);
}
treeans = min(treeans, far[cur].second);
treedia = max(treedia, far[cur].second + sfar[cur].second);
}
extern "C"{
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
int n = N;
int m = M;
int l = L;
connections.assign(n, vector<pair<int, int>>());
visited.assign(n, false);
far.assign(n, {-1, 0});
sfar.assign(n, {-1, 0});
answers.clear();
for (int i = 0; i < m; ++i) {
connections[A[i]].push_back({B[i], T[i]});
connections[B[i]].push_back({A[i], T[i]});
}
treedia = 0;
for (int i = 0; i < n; ++i) {
if (!visited[i]) {
fdfs(i, -1);
treeans = INT_MAX;
sdfs(i, -1);
answers.push_back(treeans);
dias.push_back(treedia);
}
}
sort(answers.begin(), answers.end(), greater<int>());
if (answers.size() > 2) {
return max(treedia, max(answers[0] + answers[1] + l, answers[1]+answers[2] + 2*l));
}
if (answers.size() > 1) {
return max(treedia, answers[0] + answers[1] + l);
} else {
return treedia;
}
}
}
