#include <bits/stdc++.h>
using namespace std;
void fastIO(){ios_base::sync_with_stdio(false),cin.tie(0);}
#define int long long
#define f first
#define s second
const int INF = (int)1e18;
const int MAXV = 100'020;
int V, E;
struct Edge {
int u, v, w, i;
int move (int x) {
if (x == u) return v;
else return u;
}
};
vector<Edge> edges;
vector<int> adj[MAXV];
int depth[MAXV];
int rootPath[MAXV];
vector<pair<int,int>> vecs;//{val, iEdge}
void dfs (int node, int par) {
for (int iEdge : adj[node]) {
int child = edges[iEdge].move(node), weight = edges[iEdge].w, idx = edges[iEdge].i;
if (child != par && depth[child] < depth[node]) {
// cerr << node+1 << " " << child+1 << " " << (rootPath[child]^rootPath[node]^weight) << "\n";
if (rootPath[child] ^ rootPath[node] ^ weight != 0) {
vecs.push_back({rootPath[child] ^ rootPath[node] ^ weight, iEdge});
}
}
else if (depth[child] == INF) {
// cerr << node+1 << " " << child+1 << "\n";
depth[child] = depth[node] + 1;
rootPath[child] = rootPath[node] ^ weight;
dfs(child, node);
}
}
}
int lsb (int val) {
assert(val != 0);
for (int bit = 0; bit < 32; bit++) {
if (val&(1 << bit)) {
return bit;
}
}
}
bool cmpBv (const int& a, const int& b) {
return lsb(a) < lsb(b);
}
signed main() {
fastIO();
cin >> V >> E;
for (int i = 0; i < E; i++) {
int u, v, w;
cin >> u >> v >> w;
u--, v--;
edges.push_back(Edge{u, v, w, i});
adj[u].push_back((int)edges.size()-1);
adj[v].push_back((int)edges.size()-1);
}
fill(depth, depth+V, INF);
depth[0] = 0;
dfs(0, -1);
for (int i = 0; i < V; i++) cerr << rootPath[i] << " ";
cerr << "\n";
vector<int> baseVecs;
map<int, vector<int>> baseVecsIdx;
for (pair<int,int>& val : vecs) {//{val, iEdge}
for (int& bv : baseVecs) {
if (lsb(val.f) < lsb(bv)) {
baseVecs.push_back(val.f);
if (baseVecsIdx.find(val.f) == baseVecsIdx.end()) baseVecsIdx[val.f] = {};
baseVecsIdx[val.f].push_back(val.s);
break;
}
else if (lsb(val.f) == lsb(bv)) {
baseVecsIdx[bv].push_back(val.s);
val.f ^= bv;
}
}
if (baseVecs.empty() || lsb(val.f) > lsb(baseVecs.back())) {
baseVecs.push_back(val.f);
if (baseVecsIdx.find(val.f) == baseVecsIdx.end()) baseVecsIdx[val.f] = {};
baseVecsIdx[val.f].push_back(val.s);
}
sort(baseVecs.begin(), baseVecs.end(), cmpBv);
}
cout << (int)baseVecs.size() << "\n";
for (int i = 0; i < (int)baseVecs.size(); i++) {
cout << baseVecs[i] << " ";
for (int val : baseVecsIdx[baseVecs[i]]) {
cout << val+1 << " ";
}
cout << "\n";
}
cout << "\n";
}
