#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using vi = vector<int>;
const ll INF = 1'000'000'000'000'000'000LL;
int main()
{
int N, K;
cin >> N >> K;
vvll dist(1+N, vll(1+N, INF));
for(int i = 1; i <= N; i++) dist[i][i] = 0;
vvll edge(1+N, vll(1+N, 0));
for(int e = 1; e <= N-1; e++)
{
int a, b, d;
cin >> a >> b >> d;
dist[a][b] = dist[b][a] = d;
edge[a][b] = edge[b][a] = 1;
}
for(int k = 1; k <= N; k++)
for(int i = 1; i <= N; i++)
for(int j = 1; j <= N; j++)
dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
vi par(1+N, -1);
for(int i = 2; i <= N; i++)
{
for(int j = 1; j <= N; j++)
{
if(j == i) continue;
if(dist[1][i] == dist[1][j] + dist[j][i] && edge[i][j] == 1)
{
par[i] = j;
break;
}
}
}
vector<pair<ll, int> > V;
for(int i = 1; i <= N; i++) V.push_back({dist[1][i], i});
sort(V.begin(), V.end());
vi res;
reverse(V.begin(), V.end());
vi covered(1+N, 0);
for(auto q: V)
{
int u = q.second;
if(covered[u]) continue;
int v = u;
while(v != 1 && dist[par[v]][u] <= K) v = par[v];
res.push_back(v);
for(int i = 1; i <= N; i++)
covered[i] |= (dist[v][i] <= K);
}
cout << int(res.size()) << '\n';
for(int r: res) cout << r << ' ';
cout << '\n';
}
