#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n,k;
cin >> n >> k;
assert(k <= 30);
vector<vector<pair<int,int>>> adj(n);
vector<vector<int>> good(n);
for(int i = 0;i < n - 1;i++){
int u,v,w;
cin >> u >> v >> w;
u --;
v --;
adj[u].push_back({v,w});
adj[v].push_back({u,w});
if(w <= k){
good[u].push_back(v);
good[v].push_back(u);
}
}
for(int i = 0;i < n;i++){
sort(good[i].begin(),good[i].end());
sort(adj[i].begin(),adj[i].end());
}
// for(int i = 0;i < n;i++){
// cout << i << " : \n";
// for(int &e : good[i]) cout << e << " ";
// cout << '\n';
// }
vector<vector<int>> dp(n,vector<int>(3,n));
vector<vector<int>> ndp(n,vector<int>(3));
function<void(int,int)> dfs = [&](int u,int p){
int cur = 0;
int b = 0;
for(auto pp : adj[u]){
int v = pp.first;
if(v == p) continue;
dfs(v,u);
b += dp[v][0];
}
// if u is bad
int a = 1; // u exisits
int best = n;
int bn = -1;
for(auto pp : adj[u]){
int v = pp.first;
bool f = false;
if(cur < (int)good[u].size() && good[u][cur] == v){
f = true;
cur ++;
}
if(v == p) continue;
// if u exsists
if(f) a += dp[v][1];
else a += dp[v][0];
// if u not exsits
if(f){
if(best > dp[v][2] + 1 - dp[v][0]){
best = min(best,dp[v][2] + 1 - dp[v][0]);
bn = v;
}
}
}
dp[u][0] = min(a,b + best);
if(a > b + best){
assert(bn != -1);
ndp[u][0] = bn; // make bn exists
}else{
ndp[u][0] = -1; // make own
}
// if u is good
// case 1 : u exsits
// case 2 : skip u
dp[u][1] = min(a,b);
if(a < b){
ndp[u][1] = -1; // exsits
}else{
ndp[u][1] = 0; // skip
}
// if u exsists
dp[u][2] = a - 1;
};
dfs(0,0);
// for(int i = 0;i < n;i++){
// cout << i << " : \n";
// for(int j = 0;j < 2;j++){
// cout << ndp[i][j] << " ";
// }
// cout << '\n';
// }
vector<int> ans;
function<void(int,int,int)> dfs2 = [&](int u,int p,int st){
// cout << "N " << u << " " << st << " " << ndp[u][st] << '\n';
if(ndp[u][st] == -1 && st <= 1){
ans.push_back(u);
}
if(st == 2){
ans.push_back(u);
}
int cur = 0;
int did = true;
for(auto pp : adj[u]){
int v = pp.first;
bool f = false;
if(cur < (int)good[u].size() && good[u][cur] == v){
f = true;
cur ++;
}
if(v == p) continue;
if(st == 0){
if(ndp[u][0] == -1){
// make own good
if(!did){
ans.push_back(u);
did = true;
// cout << "ADDING " << u << '\n';
}
if(f) dfs2(v,u,1);
else dfs2(v,u,0);
}else{
if(v == ndp[u][0]){
assert(f);
dfs2(v,u,2);
}else{
dfs2(v,u,0);
}
}
}else if(st == 1){
if(ndp[u][1] == -1){
if(!did){
ans.push_back(u);
did = true;
// cout << "ADDING " << u << '\n';
}
if(f) dfs2(v,u,1);
else dfs2(v,u,0);
}else{
dfs2(v,u,0);
}
}else{
if(!did){
ans.push_back(u);
did = true;
// cout << "ADDING " << u << '\n';
}
if(f) dfs2(v,u,1);
else dfs2(v,u,0);
}
}
};
// cout << dp[0][0] << " " << dp[0][2] + 1 << '\n';
if(dp[0][0] > dp[0][2] + 1){
dfs2(0,0,2);
}else{
dfs2(0,0,0);
}
cout << (int)ans.size() << '\n';
assert((int)ans.size() == min(dp[0][0],dp[0][2] + 1));
for(int &e : ans) cout << e + 1 << " ";
cout << '\n';
return 0;
}
