#include <fstream>
#include <queue>
#include <vector>
#define nmax 1001
#define mmax 10001
#define inf 1e9
using namespace std;
ifstream cin("critice.in");
ofstream cout("critice.out");
int n,m,x,y,c[nmax][nmax],flow[nmax][nmax],dist[nmax];
vector<int>v[nmax],sol;
queue<int>q;
pair<int,int>mch[mmax];
bool bfs(int s,int d){
    for(int i=1;i<=n;i++)
        dist[i]=inf;
    dist[s]=0;
    q.push(s);
    while(!q.empty()){
        int nod=q.front();
        q.pop();
        for(auto i:v[nod])
            if(dist[i]>dist[nod]+1&&flow[nod][i]<c[nod][i]){
                dist[i]=dist[nod]+1;
                q.push(i);
            }
    }
    return dist[d]!=inf;
}
int dinic(int nod,int d,int val){
    if(val==0)
        return 0;
    if(nod==d)
        return val;
    int total=0;
    for(auto i:v[nod])
        if(dist[i]==dist[nod]+1&&flow[nod][i]<c[nod][i]){
            int add=dinic(i,d,min(c[nod][i]-flow[nod][i],val-total));
            flow[nod][i]+=add;
            flow[i][nod]-=add;
            total+=add;
        }
    return total;
}
signed main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>x>>y>>c[x][y];
        c[y][x]=c[x][y];
        mch[i]={x,y};
        v[x].push_back(y);
        v[y].push_back(x);
    }
    while(bfs(1,n))
        dinic(1,n,inf);
    for(int i=1;i<=m;i++){
        int x=mch[i].first,y=mch[i].second;
        if((flow[x][y]==c[x][y]||(flow[y][x]==c[y][x]&&c[y][x]!=0))
            sol.push_back(i);
    }
    cout<<sol.size()<<'\n';
    for(auto i:sol)
        cout<<i<<'\n';
    return 0;
}