/*************************************
* author: marvinthang *
* created: 06.06.2023 15:55:43 *
*************************************/
#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define left ___left
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x) >> (i) & 1)
#define __builtin_popcount __builtin_popcountll
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define REPD(i, n) for (int i = (n); i--; )
#define FOR(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); --i >= _a; )
#define FORE(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORDE(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define scan_op(...) istream & operator >> (istream &in, __VA_ARGS__ &u)
#define print_op(...) ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
#include "debug.h"
#else
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define DB(...) 23
#define db(...) 23
#define debug(...) 23
#endif
template <class U, class V> scan_op(pair <U, V>) { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>) { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>) { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b) { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b) { if (a < b) { a = b; return true; } return false; }
// end of template
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
vector <vector <pair <int, int>>> adj(N);
REP(i, M) {
adj[A[i]].emplace_back(T[i], B[i]);
adj[B[i]].emplace_back(T[i], A[i]);
}
vector <int> distu(N, -1), distv(N, -1);
vector <int> f;
int r = 0;
REP(i, N) if (distu[i] == -1) {
vector <int> ver;
auto bfs = [&] (int s, vector <int> &dist, bool f = false) {
queue <int> q;
dist[s] = 0;
q.push(s);
int ma = s;
while (!q.empty()) {
int u = q.front(); q.pop();
if (f) ver.push_back(u);
if (dist[ma] < dist[u]) ma = u;
for (auto [w, v]: adj[u]) if (dist[v] == -1) {
dist[v] = dist[u] + w;
q.push(v);
}
}
return ma;
};
int u = bfs(i, distu, true);
for (int x: ver) distu[x] = -1;
int v = bfs(u, distu);
bfs(v, distv);
maximize(r, distu[v]);
int mi = 1e9;
for (int u: ver) minimize(mi, max(distu[u], distv[u]));
f.push_back(mi);
}
if (M == N - 1) return r;
int res = 1e9;
sort(ALL(f));
REP(i, f.size()) {
vector <int> v {f[i]};
REPD(j, f.size()) if (j != i) {
v.push_back(f[j] + L);
if (v.size() == 3) break;
}
sort(v.rbegin(), v.rend());
minimize(res, v[0] + v[1]);
}
return max(r, res);
}
#ifdef LOCAL
#include <stdio.h>
#include <stdlib.h>
#include "dreaming.h"
#define fail(s, x...) do { \
fprintf(stderr, s "\n", ## x); \
exit(1); \
} while(0)
#define MAX_N 100000
static int A[MAX_N];
static int B[MAX_N];
static int T[MAX_N];
int main() {
int N, M, L, i;
int res;
FILE *f = fopen("dreaming.in", "r");
if (!f)
fail("Failed to open input file.");
res = fscanf(f, "%d%d%d", &N, &M, &L);
for (i = 0; i < M; i++)
res = fscanf(f, "%d%d%d", &A[i], &B[i], &T[i]);
fclose(f);
int answer = travelTime(N, M, L, A, B, T);
printf("%d\n", answer);
return 0;
}
#endif
