#include <bits/stdc++.h>
#define int long long
using namespace std;
int const mxN = 3e5+5;
int n,k;
vector<pair<int,int>> adj [mxN];
vector<int> put;
bool vis[mxN];
void dfs ( int i, int p, int d) {
if(d>k) return;
vis[i] = 1;
for(auto it:adj[i]) {
if(it.first==p) continue;
dfs(it.first, i, d+it.second);
}
}
vector<int> ans;
void check() {
memset(vis,0,sizeof vis);
for(auto it:put) dfs(it,0,0);
for(int i=1; i<=n; i++) if(!vis[i]) return;
if(ans.size()>put.size() || ans.empty()) ans = put;
}
void solve ( int i ) {
if(i==n+1) { check(); return; }
solve(i+1);
put.push_back(i);
solve(i+1);
put.pop_back();
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
cin>>n>>k;
for(int i=0; i<n-1; i++) {
int a,b,c; cin>>a>>b>>c;
adj[a].push_back({b,c}), adj[b].push_back({a,c});
}
if(n<=17) {
solve(1);
cout<<ans.size()<<'\n';
for(auto it:ans) cout<<it<<' ';
}
else {
cout<<n<<'\n';
for(int i=1; i<=n; i++) cout<<i<<' ';
}
return 0;
}
