using namespace std;
#include<iostream>
#include<fstream>
#include<vector>
#include<cstring>
#define pb push_back
#define nmax 1005
#define mmax 10005
#define oo 0x3f3f3f3f
int N,M;
struct edge{
int x,y;};
ofstream fout("critice.out");
 
vector<int> G[nmax];
 
int C[nmax][nmax], F[nmax][nmax];
edge a[mmax];
int ante[nmax],q[nmax],viz[nmax];
 
int flow;
bool bif1[nmax],bif2[nmax];
 
bool BFS()
{   int u;
    memset(q,0,sizeof(q));
    memset(ante,0,sizeof(ante));
    memset(viz,0,sizeof(viz));
    vector<int>::iterator it;
    viz[1]=1;
    q[++q[0]]=1;
    int front=1;
 
    while(front<=q[0])
    {
        u=q[front++];
        for(it=G[u].begin();it<G[u].end();it++)
        {
            if(!viz[*it] && C[u][*it]>F[u][*it])
            {
                viz[*it]=1;
                q[++q[0]]=*it;
                ante[*it]=u;
            }
        }
    }
 
 
    return viz[N];
}
 
 
void DFS1(int nod)
{
    bif1[nod]=1;
    for(vector<int>::iterator it=G[nod].begin();it<G[nod].end();it++)
    {
        if(!bif1[*it] && F[nod][*it]<C[nod][*it] && F[*it][nod]<C[*it][nod])
        {
            DFS1(*it);
        }
    }
}
 
void DFS2(int nod)
{
    bif2[nod]=1;
    for(vector<int>::iterator it=G[nod].begin();it<G[nod].end();it++)
    {
        if(!bif2[*it] && F[nod][*it]<C[nod][*it] && F[*it][nod]<C[*it][nod])
        {
            DFS2(*it);
        }
    }
}
void solve()
{int i;
    vector<int>::iterator it;
     int fmin;
    for(flow=0;BFS();)
    {
        fmin=oo;
        for(it=G[N].begin();it<G[N].end();it++)
        if(viz[*it])
        {
            fmin=C[*it][N]-F[*it][N];
 
            for(i=*it;i>1;i=ante[i])
            {
                fmin=min(fmin,C[ante[i]][i]-F[ante[i]][i]);
 
            }
 
            F[*it][N]+=fmin;
            F[N][*it]-=fmin;
            for(i=*it;i>1;i=ante[i])
            {
                F[ante[i]][i]+=fmin;
                F[i][ante[i]]-=fmin;
            }
           flow+=fmin;
        }
 
    }
 
 
    DFS1(1);
    DFS2(N);
    vector<int> sol;
    for(i=1;i<=M;i++)
    {
      if(C[a[i].x][a[i].y]==F[a[i].x][a[i].y] && bif1[a[i].x] && bif2[a[i].y])
           sol.pb(i);
           else if(C[a[i].y][a[i].x]==F[a[i].y][a[i].x] && bif1[a[i].y] && bif2[a[i].x])
                 sol.pb(i);
    }
    fout<<sol.size()<<"\n";
    for(i=0;i<sol.size();i++)
      fout<<sol[i]<<"\n";
}
 
void cit()
{
    int i,x,y,z;
 
    ifstream fin("critice.in");
    fin>>N>>M;
 
    for(i=1;i<=M;i++)
    {
        fin>>x>>y>>z;
        a[i].x=x;
        a[i].y=y;
        G[x].pb(y);
        G[y].pb(x);
        C[x][y]+=z;
 
        C[y][x]+=z;
        F[x][y]=0;
        F[y][x]=0;
    }
    fin.close();
 
}
 
int main()
{
   cit();
   solve();
   fout.close();
 
   return 0;
}