#include <iostream>
#include<fstream>
#include<vector>
#include<algorithm>
#define inf 1000000
using namespace std;
ifstream f("critice.in");
ofstream g("critice.out");
int sz,c[1000000],C[1001][1001],F[1001][1001],k,i,flow,fmn,n,m,father[1001],x,y,cst,start,finish,j;
vector<int>v[1001],sol;
bool viz[1001],taken[10001];
struct muchie
{
    int x,y;
};
muchie mu[10001];
int bfs()
{
    sz=1;
    c[1]=1;
    int i,nod;
    for(i=1; i<=n; i++)
        viz[i]=0;
    viz[1]=1;
    for(i=1; i<=sz; i++)
    {
        nod=c[i];
        if(nod==n)
            continue;
        for(k=0; k<v[nod].size(); k++)
        {
            int vertex=v[nod][k];
            if(viz[vertex] || F[nod][vertex]==0)
                continue;
            c[++sz]=vertex;
            viz[vertex]=1;
            father[vertex]=nod;
        }
    }
    return viz[n];
}
void cauta(int a,int b)
{
    bool ok=1;
    for(int i=1; i<=m && ok; i++)
        if(mu[i].x==a && mu[i].y==b || (mu[i].x==b && mu[i].y==a))
        {
            ok=0;
            if(!taken[i])
            sol.push_back(i),taken[i]=1;
        }
}
void df(int nod)
{
    viz[nod]=1;
    if(nod==1)
        start=1;
    else if(nod==n)
        finish=1;
    if(!finish || !start)
    for(int k=0;k<v[nod].size();k++)
        if(!viz[v[nod][k]] && F[nod][v[nod][k]] && F[v[nod][k]][nod])
            df(v[nod][k]);
}
int main()
{
    f>>n>>m;
    for(i=1; i<=m; i++)
    {
        f>>x>>y>>cst;
        v[x].push_back(y);
        v[y].push_back(x);
        F[x][y]=cst;
        F[y][x]=cst;
        mu[i].x=x;
        mu[i].y=y;
    }
    while(bfs())
        for(k=0; k<v[n].size(); k++)
        {
            int nod=v[n][k];
            if(F[nod][n]==0 || !viz[nod])
                continue;
            father[n]=nod;
            fmn=inf;
            for(i=n; i!=1; i=father[i])
                fmn=min(fmn,F[father[i]][i]);
            for(i=n; i!=1; i=father[i])
            {
                F[father[i]][i]-=fmn;
                F[i][father[i]]+=fmn;
            }
            flow+=fmn;
        }
    //cout<<flow<<'\n';
    for(i=1;i<=n;i++)
        for(k=0;k<v[i].size();k++)
        if(!F[i][v[i][k]])
    {
        int vertex=v[i][k];
        start=finish=0;
        for(j=1;j<=n;j++)
            viz[j]=0;
        df(i);
        if(!(start && finish))
        {
            for(j=1;j<=n;j++)
                viz[j]=0;
            df(v[i][k]);
        }
        if(start&& finish )
            cauta(i,v[i][k]);
    }
    sort(sol.begin(),sol.end());
    g<<sol.size()<<'\n';
    for(i=0; i<sol.size(); i++)
        g<<sol[i]<<'\n';
}