#include <fstream>
#include <vector>

using namespace std;

ifstream in("critice.in");
ofstream out("critice.out");
int n, m, ok, ans;
vector<pair<int, int>> v[1005];
pair<int, int> muc[20005];
int viz[1005];
vector<int> st;
int INF = (1 << 30);

void dfs(int nod, int flux, int cmin)
{
    viz[nod] = 1;

    if(nod == n)
    {
        ok = 1;

        for(auto it: st)
        {
            if(it <= m)
            {
                muc[it].first += flux;
                muc[it + m].first -= flux;
            }
            else
            {
                muc[it].first += flux;
                muc[it - m].first -= flux;
            }
        }

        return;
    }

    for(auto it: v[nod])
    {
        if(viz[it.first] == 0 && muc[it.second].second - muc[it.second].first >= cmin)
        {
            st.push_back(it.second);

            dfs(it.first, min(flux, muc[it.second].second - muc[it.second].first), cmin);

            st.pop_back();
        }
    }
}

void dfs2(int nod)
{
    viz[nod] = 1;

    for(auto it: v[nod])
    {
        if(viz[it.first] == 0 && muc[it.second].second - muc[it.second].first > 0)
        {
            dfs2(it.first);
        }
    }
}

int main()
{
    in>>n>>m;

    int x, y, z;
    int cmax = 0;
    for(int i = 1; i<=m; i++)
    {
        in>>x>>y>>z;

        v[x].push_back({y, i});
        muc[i] = {0, z};

        v[y].push_back({x, i + m});
        muc[i + m] = {0, z};

        cmax = max(cmax, z);
    }

    for(int i = cmax; i>=1; i /= 2)
    {
        ok = 1;
        while(ok == 1)
        {
            ok = 0;

            for(int j = 1; j<=n; j++)
            {
                viz[j] = 0;
            }
            st.clear();

            dfs(1, INF, i);
        }
    }

    for(int i = 1; i<=n; i++)
    {
        viz[i] = 0;
    }
    dfs2(1);

    for(int i = 1; i<=n; i++)
    {
        if(viz[i] == 1)
        {
            for(auto it: v[i])
            {
                if(viz[it.first] == 0)
                {
                    ans++;
                }
            }
        }
    }

    out<<ans<<'\n';
    for(int i = 1; i<=n; i++)
    {
        if(viz[i] == 1)
        {
            for(auto it: v[i])
            {
                if(viz[it.first] == 0)
                {
                    if(it.second <= m)
                    {
                        out<<it.second<<'\n';
                    }
                    else
                    {
                        out<<it.second - m<<'\n';
                    }
                }
            }
        }
    }

    return 0;
}