#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
using namespace std;
int c[1014][1014],viz1[1014],viz2[1014],n,m,prec[1014],flux[1014][1014];
vector <int> v[1014];
vector <pair <int, int> > muchie;
bitset <1014> apar;
int bfs ()
{
    int i,j,nod,nodc;
    for (i=1;i<=n;i++)
    {
        apar[i]=0;
        prec[i]=0;
    }
    queue <int> q;
    q.push(1);
    apar[1]=1;
    prec[1]=1;
    while (!q.empty())
    {
        nod=q.front();
        q.pop();
        for (i=0;i<v[nod].size();i++)
        {
            nodc=v[nod][i];
            if (!apar[nodc])
                if (c[nod][nodc]!=flux[nod][nodc] && prec[nodc]==0)
                {
                    prec[nodc]=nod;
                    apar[nodc]=1;
                    if (nodc!=n)
                        q.push(nodc);
                }
        }
    }
    return apar[n];
}
struct cmp
{
    bool operator () (int a, int b)
    {
        return a>b;
    }
};
inline int saturare (int n1, int n2)
{
    if (c[n1][n2]==flux[n1][n2])
        return 1;
    if (c[n2][n1]==flux[n2][n1])
        return 1;
    return 0;
}
void bfs2( int nod, int viz[])
{
    int i;
    viz[nod]=1;
    for (i=0;i<v[nod].size();i++)
        if (viz[v[nod][i]]==0 && saturare(nod,v[nod][i])==0 && c[nod][v[nod][i]]>flux[nod][v[nod][i]])
            bfs2(v[nod][i], viz);

}
inline int conditie (int n1, int n2)
{
    if (viz1[n1]==1 && viz2[n2]==1)
        return 1;
    if (viz1[n2]==1 && viz2[n1]==1)
        return 1;
    return 0;
}
int main()
{
    int i,j,z,x,y,flux_curent,nod,nodc,nod1,nod2;
    fstream f,g;
    f.open("critice.in",ios::in);
    g.open("critice.out",ios::out);
    f>>n>>m;
    for (i=1;i<=m;i++)
    {
        f>>x>>y>>z;
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y]=z;
        c[y][x]=z;
        muchie.push_back(make_pair(x,y));
    }
    int max_flow=0,numar=0;
    while (bfs())
    {
        for (i=0;i<v[n].size();i++)
            if (apar[v[n][i]]==1 && c[v[n][i]][n]-flux[v[n][i]][n]>0 && prec[v[n][i]])
            {
                nod=v[n][i];
                flux_curent= c[v[n][i]][n]-flux[v[n][i]][n];
                do
                {
                    nodc=prec[nod];
                    flux_curent=min(flux_curent,c[nodc][nod]-flux[nodc][nod]);
                    nod=nodc;
                }while (nod!=1);
                if (flux_curent<=0) continue;
                nod=v[n][i];
               // max_flow+=flux_curent;
                flux[nod][n]+=flux_curent;
                flux[n][nod]-=flux_curent;
                do
                {
                    nodc=prec[nod];
                    flux[nodc][nod]+=flux_curent;
                    flux[nod][nodc]-=flux_curent;
                    nod=nodc;
                }while (nod!=1);
            }
    }
   // cout<<max_flow;
    bfs2(1, viz1);
    bfs2(n, viz2);
    priority_queue<int, vector<int>, cmp > heap;// fara functia cmp mi-l face in ord descrescatoare
    for (i=0;i<muchie.size();i++)
    {
        nod1=muchie[i].first;
        nod2=muchie[i].second;
        if (saturare(nod1,nod2) && conditie(nod1, nod2))
            heap.push(i+1);
    }
    g<<heap.size()<<"\n";
    while (!heap.empty())
    {
        g<<heap.top()<<'\n';
        heap.pop();
    }
}