// ia - Critice
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

const int INF = 1e9;
int n, m;

vector<vector<int>> residual;
vector<bool> visited;

vector<vector<int>> adj;
vector<int> parent;
vector<pair<int, int>> edges;

bool bfs() {
    queue<int> q;
    for (auto& p : parent) { 
        p = 0;
    }

    q.emplace(1);
    parent[1] = -1;

    while (!q.empty() && !parent[n]) {
        int current_node = q.front();
        q.pop();

        if (current_node == n) {
            continue;
        }

        for (auto &nei : adj[current_node]) {
            if (!parent[nei] && residual[current_node][nei]) {
                parent[nei] = current_node;
                q.emplace(nei);
            }
        }
    }

    return parent[n] != 0;
}

void edmonds_karp() {
    parent.resize(n + 1, 0);

    while (bfs()) {
        for (auto& node : adj[n]) {
            // daca am vizitat nodul si mai pot pompa
            if (parent[node] != 0 && residual[node][n]) {
                parent[n] = node;

                int flow = INF;
                for (int crt_node = n; crt_node != 1; crt_node = parent[crt_node]) {
                    flow = min(flow, residual[parent[crt_node]][crt_node]);
                }

                if (!flow) {
                    continue;
                }

                for (int crt_node = n; crt_node != 1; crt_node = parent[crt_node]) {
                    residual[parent[crt_node]][crt_node] -= flow;
                    residual[crt_node][parent[crt_node]] += flow;
                }

            }
        }
    }
}

void dfs(int node) {
    visited[node] = true;

    for (auto &nei : adj[node]) {
        if (!visited[nei] && residual[node][nei]) {
            dfs(nei);
        }
    }
}

int main()
{
    ifstream cin("critice.in");
    ofstream cout("critice.out");

    cin >> n >> m;

    residual.resize(n + 1, vector<int>(n + 1, 0));
    adj.resize(n + 1);

    while (m--) {
        int x, y, z;
        cin >> x >> y >> z;
        adj[x].emplace_back(y);
        adj[y].emplace_back(x);

        residual[x][y] = residual[y][x] = z;
        edges.emplace_back(x, y);
    }

    // FLUX!
    edmonds_karp();

    visited.resize(n + 1, false);
    dfs(1);

    vector<int> critice;
    for (int i = 0; i < edges.size(); ++i) {
        if (visited[edges[i].first] != visited[edges[i].second]) {
            critice.emplace_back(i + 1);
        }
    }

    cout << critice.size() << '\n';
    for (auto& edge_index : critice) {
        cout << edge_index << '\n';
    }

    return 0;
}