#include<iostream>
#include<cmath>
#include<cstring>
#include<cassert>
#include<string>
#include<queue>
#include<deque>
#include<stack>
#include<algorithm>
#include<unordered_map>
#include<map>
#include<vector>
#include<set>
#include<unordered_set>
#include<bitset>
#include<climits>
#include<numeric>
#include<functional>
#include<iomanip>
#include<random>
#ifdef YJL
#include<debug.h>
#else
#define debug(args...)0
#define debug_n(a,n)0
#endif
using namespace std;
typedef long long ll;
struct Dsu {
    vector<int> fa, sz;
    Dsu(int n): fa(n),sz(n,1) {
        iota(fa.begin(), fa.end(), 0);
    }
    bool unite(int x, int y) {
       x=get(x), y=get(y);
       if(x==y) return false;
       fa[x]=y;
       sz[y]+=sz[x];
       return true;
    }
    int get(int x) {
        return fa[x]==x ? x: fa[x]=get(fa[x]);
    }
    int size(int x) {
        return sz[get(x)];
    }
};
const int N = 2e5 + 10;
struct ty {
    int t,l,next;
} edge[int(2e6)+10];
int en,head[N];
void initGraph(int n) {
    fill_n(head+1,n,-1),en=0;
}
void addEdge(int x,int y,int z=0) {
    edge[en]={y,z,head[x]};
    head[x]=en++;
}
int n,m,used[N],inTree[N];

vector<int> que;
bool dfs(int u,int st,int preIdx=-1) {
    for(int i=head[u]; ~i; i=edge[i].next) {
        int v=edge[i].t;
        if(!inTree[i/2]||(i^1)==preIdx) continue;
        if(!used[i/2]) que.push_back(i/2);
        if(v==st) {
            inTree[que.back()]=0;
            cout<<que.back()+1<<" ";
            que.clear();
            return true;
        }
        if(dfs(v,st,i))
            return true;
        if(!used[i/2]) que.pop_back();
    }
    return false;
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    cin>>n>>m;
    initGraph(n);
    vector<tuple<ll,int,int,int>> e;
    for(int i=0,u,v,w; i<m; ++i) {
        cin>>u>>v>>w;
        ll temp=1ll*w*n-(i<n-1);// 原来小的还是小，原来相同的看谁原边多
        e.emplace_back(temp,u,v,i);
        addEdge(u,v);
        addEdge(v,u);
        if(i<n-1)
            inTree[i]=1;
    }

    sort(e.begin(),e.end());
    int vary=0;
    Dsu d(n+1);
    for(auto [w,u,v,id]:e) {
        if(!d.unite(u,v)) continue;
        used[id]=1;
        if(!inTree[id]) vary++;
    }
    
    cout<<vary<<'\n';
    // 寻找方案
    for(int i=0; i<m; ++i) {
        if(used[i] && !inTree[i]) {
            inTree[i]=1;
            dfs(edge[i*2].t,edge[i*2].t);
            cout<<i+1<<"\n";
        }
    }
    return 0;
}
/*




*/