#include<fstream>
#include<cstring>
#include<vector>
#include<stdlib.h>
using namespace std;
int c[1001][1001],f[1001][1001],t[1001],viz[1001],m,n,q[1000001],fl,viz1[2][10001],sol[10001];
vector<pair<int,int> >muc[1001];
ifstream fin("critice.in");
ofstream fout("critice.out");
struct muchie
{
 int x,y;
}v[10001];
void citire()
{
    int x,y,val;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y>>val;
        c[x][y]=val;
        c[y][x]=val;
        muc[x].push_back(make_pair(y,i));
        muc[y].push_back(make_pair(x,i));
        v[i].x=x;
        v[i].y=y;
    }
}

int bfs()
{
    int p=1,u=1,nod;
    viz[1]=1;
    q[1]=1;
    while(p<=u)
    {
        for(int i=1;i<=n;i++)
        {
            if(f[q[p]][i]==c[q[p]][i] || viz[i]==1)
            continue;

            q[++u]=i;
            t[i]=q[p];
            viz[i]=1;
        }
        p++;
    }
    return viz[n];
}

int parinti(int nod)
{
    int mini=c[nod][n]-f[nod][n];
    while(nod!=1)
    {
        mini=min(mini,c[t[nod]][nod]-f[t[nod]][nod]);
        nod=t[nod];
    }
    return mini;
}

void detFlux(int nod,int fl)
{
    f[n][nod]-=fl;
    f[nod][n]+=fl;
    while(nod!=1)
    {
        f[nod][t[nod]]-=fl;
        f[t[nod]][nod]+=fl;
        nod=t[nod];
    }
}

void bfs1(int srs,int k)
{
    int p,u,nod;
    p=u=1;
    q[1]=srs;
    viz1[k][srs]=1;
    while(p<=u)
    {
        nod=q[p];
        for(int i=0;i<muc[nod].size();i++)
        {
            if(viz1[k][muc[nod][i].first]==0 && c[nod][muc[nod][i].first]>abs(f[nod][muc[nod][i].first]))
            {
                q[++u]=muc[nod][i].first;
                viz1[k][muc[nod][i].first]=1;

            }
        }
        p++;
    }
}

int main()
{
    citire();
    while(bfs())
    {
        for(int i=1;i<=n;i++)
        {
            if(viz[i]==0 || f[i][n]==c[i][n])
                continue;

            fl=parinti(i);
            if(fl==0)
                continue;
            detFlux(i,fl);
        }
        memset(viz,0,sizeof(viz));
        memset(t,0,sizeof(t));
    }

    bfs1(1,0);
    bfs1(n,1);
    int nr=0;
    for(int i=1;i<=m;i++)
    {
        if((viz1[0][v[i].x]==1 || viz1[0][v[i].y]==1) && (viz1[1][v[i].x]==1 || viz1[1][v[i].y]==1)  && c[v[i].x][v[i].y]==abs(f[v[i].x][v[i].y]))
        {
            sol[++nr]=i;
        }
    }
    fout<<nr<<"\n";
    for(int i=1;i<=nr;i++)
    {
        fout<<sol[i]<<"\n";
    }
    return 0;
}