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

using namespace std;

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

vector<bool> vizitat;

struct Edge
{
    int v, u;
    long long cap, flow = 0;
    Edge(int v, int u, long long cap)
    {
        this->v = v;
        this->u = u;
        this->cap = cap;
    }
};

struct Dinic
{
    long long const inf_flow = numeric_limits<long long>::max();
    vector<Edge> edges;
    vector<vector<int>> adjList;
    int n, m = 0;
    int s, t;
    vector<int> level, ptr;
    queue<int> q;
    explicit Dinic(int n, int s, int t)
    {
        this->n = n;
        this->s = s;
        this->t = t;
        adjList.resize(n);
        level.resize(n);
        ptr.resize(n);
    }
    void add_edge(int v, int u, long long capacity)
    {
        edges.emplace_back(v, u, capacity);
        edges.emplace_back(u, v, capacity);
        adjList[v].push_back(m);
        adjList[u].push_back(m + 1);
        m += 2;
    }

    bool bfs()
    {
        while (q.empty() == false)
        {
            int v = q.front();
            q.pop();
            for (auto id : adjList[v])
            {
                if (edges[id].cap - edges[id].flow < 1)
                    continue;
                if (level[edges[id].u] != -1)
                    continue;
                level[edges[id].u] = level[v] + 1;
                q.push(edges[id].u);
            }
        }
        return level[t] != -1;
    }

    long long dfs(int v, long long pushed)
    {
        if (pushed == 0)
            return 0;
        if (v == t)
            return pushed;
        int siz = static_cast<int>(adjList[v].size());
        for (int &cid = ptr[v]; cid < siz; cid++)
        {
            int id = adjList[v][cid];
            int u = edges[id].u;
            if (level[v] + 1 != level[u] || edges[id].cap - edges[id].flow < 1)
                continue;
            long long tr = dfs(u, min(pushed, edges[id].cap - edges[id].flow));
            if (tr == 0)
                continue;
            edges[id].flow += tr;
            edges[id ^ 1].flow -= tr;
            return tr;
        }
        return 0;
    }

    long long flow()
    {
        long long f = 0;
        while (true)
        {
            fill(level.begin(), level.end(), -1);
            level[s] = 0;
            q.push(s);
            if (!bfs())
                break;
            fill(ptr.begin(), ptr.end(), 0);
            while (long long pushed = dfs(s, inf_flow))
                f += pushed;
        }
        return f;
    }
    void dfs(int v)
    {
        vizitat[v] = true;
        int siz = static_cast<int>(adjList[v].size());
        for (int i = 0; i < siz; i++)
        {
            int id = adjList[v][i];
            int u = edges[id].u;
            if (vizitat[u] == false && edges[id].cap - edges[id].flow >= 1)
                dfs(u);
        }
    }
};

int main()
{
    int n, m;
    fin >> n >> m;
    Dinic solve(n + 1, 1, n);
    vizitat.assign(n + 1, false);
    vector<pair<int, int>> inp(m);
    for (int i = 0; i < m; i++)
    {
        int x, y, z;
        fin >> x >> y >> z;
        inp[i] = {x, y};
        solve.add_edge(x, y, z);
    }
    solve.flow();
    //for (auto a : solve.edges)
    //{
    //    cout << a.v << " " << a.u << " " << a.flow << "\n";
    //}
    solve.dfs(1);
    vector<int> sol;
    for (int i = 0; i < m; i++)
    {
        if (vizitat[inp[i].first] != vizitat[inp[i].second])
            sol.push_back(i);
    }
    fout << sol.size() << "\n";
    for (auto a : sol)
        fout << a + 1 << "\n";
    return 0;
}