#include "bits/stdc++.h"
#include "dreaming.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 1e5 + 5;
const int inf = 1e9;
int n, m, l;
int dep[maxn];
vector<pair<int, int>> g[maxn];
pair<int, int> f[maxn];
pair<int, int> opt[maxn];
bool vis[maxn];
int cdist;
void upd(pair<int, int> &ft, int x) {
vector<int> a;
a.push_back(ft.first);
a.push_back(ft.second);
a.push_back(x);
sort(a.begin(), a.end());
ft = make_pair(a[2], a[1]);
}
void pre_dfs(int u, int prev) {
vis[u] = 1;
f[u] = make_pair(0, -inf);
for(auto e:g[u]) {
int v = e.first, w = e.second;
if(v == prev) continue;
dep[v] = dep[u] + w;
pre_dfs(v, u);
upd(f[u], f[v].first + w);
}
}
void reroot(int u, int prev) {
opt[u] = f[u];
if(cdist == -1 || f[cdist].first > f[u].first) {
cdist = u;
}
debug(u, f[u]);
for(auto e:g[u]) {
int v = e.first, w = e.second;
if(v == prev) continue;
pair<int, int> mem = f[v];
if(f[u].first == f[v].first + w) {
upd(f[v], f[u].second + w);
} else {
upd(f[v], f[u].first + w);
}
reroot(v, u);
f[v] = mem;
}
}
int find_center(int root) {
dep[root] = 0;
pre_dfs(root, 0);
cdist = -1;
reroot(root, 0);
return cdist;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
n = N;
m = M;
l = L;
for(int i = 0; i < m; ++i) {
int u = A[i], v = B[i], w = T[i];
++u, ++v;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
}
set<array<int, 3>> s;
for(int i = 1; i <= n; ++i) {
if(vis[i]) continue;
pre_dfs(i, 0);
int center = find_center(i);
debug(i, center, opt[center]);
s.insert({opt[center].first, opt[center].second, center});
}
while((int)s.size() > 1) {
array<int, 3> ft = *s.begin();
s.erase(s.begin());
array<int, 3> se = *s.rbegin();
s.erase(--s.end());
pair<int, int> cft = {-inf, -inf};
upd(cft, ft[0]), upd(cft, ft[1]), upd(cft, se[0] + l);
// upd(cft, se[1] + l);
pair<int, int> cse = {-inf, -inf};
upd(cse, ft[0] + l), upd(cse, se[0]), upd(cse, se[1]);
// upd(cse, ft[1] + l);
debug(cft, cse, ft, se);
if(cft < cse) {
s.insert({cft.first, cft.second, ft[2]});
} else {
s.insert({cse.first, cse.second, se[2]});
}
}
array<int, 3> ft = *s.begin();
return ft[0] + ft[1];
}
#ifdef duc_debug
signed main() {
cin >> n >> m >> l;
int a[m], b[m], t[m];
for(int i = 0; i < m; ++i) {
int u, v, w; cin >> u >> v >> w;
a[i] = u, b[i] = v, t[i] = w;
}
cout << travelTime(n, m, l, a, b, t);
}
#endif
/*
11 8 3
0 1 3
1 2 1
0 3 2
4 5 4
4 6 2
7 8 7
7 9 4
8 10 5
7 5 3
0 1 3
1 2 1
0 3 2
4 5 4
4 6 2
*/
