#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 INF=2e9;

vector<int>ans;
vector<int>v[NMAX];
vector<pair<int,int>>edge;

int crit[NMAX][NMAX];
int flux[NMAX][NMAX];
int total[NMAX];
int t[NMAX];
bool viz[NMAX];
int n;

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

bool bfs(int p)
{
    for(int i=1;i<=n;i++)
        viz[i]=false;
    queue<int>q;
    q.push(p);
    viz[p]=true;
    while(!q.empty())
    {
        int 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);
                t[i]=p;
                viz[i]=true;
            }
        }
    }
    return false;
}


int main()
{
    int m,i,j,x,y,c,mini=INF;
    long long maxi=0;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        v[x].push_back(y);
        v[y].push_back(x);
        flux[x][y]=c;
        flux[y][x]=c;
        edge.push_back(make_pair(x,y));
    }
    while(bfs(1))
    {
        for(auto i:v[n])
        {
            if(!viz[i] || flux[i][n]<=0)
                continue;
            mini=INF;
            t[n]=i;
            x=n;
            while(x!=1)
            {
                mini=min(mini,flux[t[x]][x]);
                x=t[x];
            }
            if(mini==0)
                continue;
            x=n;
            while(x!=1)
            {
                flux[x][t[x]]+=mini;
                flux[t[x]][x]-=mini;
                x=t[x];
            }
        }
    }
    bool key=true;
    for(i=1;i<=n;i++)
        viz[i]=0;
    dfs(1,key);
    for(i=1;i<=n;i++)
        viz[i]=0;
    dfs(n,key);
    int memo=edge.size();
    for(i=0;i<memo;i++)
        if(crit[edge[i].first][edge[i].second]==2)
            ans.push_back(i+1);
    fout<<ans.size()<<"\n";
    for(auto i:ans)
        fout<<i<<"\n";
    return 0;
}