#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

///#include <tryhardmode>
///#include <GOMDODE::ON>

using namespace std;

ifstream fin("critice.in");
ofstream fout("critice.out");

const int NMAX=1e3+5;
const int MAXVAL=1e9;

vector<int>v[NMAX];
vector<pair<int,int>>v2;

int crit[NMAX][NMAX];
int flux[NMAX][NMAX];
int total[NMAX];
int t[NMAX];

bool viz[NMAX];

int n;
int kon;

void dfs(int p)
{
    viz[p]=1;
    for(auto i:v[p])
    {
        if(!viz[i])
        {
            if(flux[p][i]==0 || flux[i][p]==0)
            {
                crit[p][i]++;
                crit[i][p]++;
            }
            else
                dfs(i);
        }
    }
}

bool bfs(int p)
{
    int i;
    queue<int>q;
    for(i=1;i<=n;i++)
    {
        t[i]=0;
        viz[i]=0;
    }
    q.push(1);
    viz[1]=true;
    while(!q.empty())
    {
        p=q.front();
        q.pop();
        if(p==n)
            return true;
        for(auto i:v[p])
        {
            if(!viz[i] && flux[p][i]>0)
            {
                q.push(i);
                viz[i]=1;
                t[i]=p;
            }
        }
    }
    return false;
}

void solve_n_reset()
{
    int i;
    for(i=1;i<=n;i++)
        viz[i]=0;
    dfs(1);
    for(i=1;i<=n;i++)
        viz[i]=0;
    dfs(n);
}

int main()
{
    int i,j,m,a,b,c,minim,x;
    long long maxim=0;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>a>>b>>c;
        v2.push_back(make_pair(a,b));
        flux[a][b]=c;
        flux[b][a]=c;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    while(bfs(1))
    {
        for(auto i:v[n])
        {
            if(!viz[i])
                continue;
            if(flux[i][n]<=0)
                continue;
            minim=MAXVAL;
            t[n]=i;
            x=n;
            while(x!=1)
            {
                minim=min(minim,flux[t[x]][x]);
                x=t[x];
            }
            if(minim==0)
                continue;
            maxim=maxim+minim;
            x=n;
            while(x!=1)
            {
                flux[x][t[x]]=flux[x][t[x]]+minim;
                flux[t[x]][x]=flux[t[x]][x]-minim;
                x=t[x];
            }
        }
    }
    solve_n_reset();
    for(i=0;i<v2.size();i++)
        if(crit[v2[i].first][v2[i].second]>1)
            total[++kon]=i+1;
    fout<<kon<<"\n";
    for(i=1;i<=kon;i++)
        fout<<total[i]<<"\n";
    return 0;
}