#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; }