#include <cstdio>
#include <iostream>
#include <queue>
#include <vector>
#include <cassert>

using namespace std;

struct flow {
  const int INF = (int) 1e9;
  struct edge {
    int cap;
    int to;
    int nxt;
    int init;
  };
  int n;
  vector<int> pos;
  vector<int> level;
  vector<int> head;
  vector<edge> edges;
  vector<bool> way1;
  vector<bool> wayn;
  void init(int nn) {
    n = nn;

    pos.clear();
    level.clear();
    edges.clear();
    head.clear();

    head.resize(n + 1, -1);
    pos.resize(n + 1);
    level.resize(n + 1);
  }
  void add(int a, int b, int c) {
    edges.push_back({c, b, head[a], (int) edges.size() / 2 + 1});
    edges.push_back({c, a, head[b], -1});

    head[a] = (int) edges.size() - 2;
    head[b] = (int) edges.size() - 1;
  }
  int dfs(int a, int cap) {
    if (!cap || a == n) {
      return cap;
    }
    while (pos[a] != -1) {
      int i = pos[a];
      pos[a] = edges[i].nxt;
      if (edges[i].cap > 0 && level[edges[i].to] == 1 + level[a]) {
        int x = dfs(edges[i].to, min(cap, edges[i].cap));
        if (x > 0) {
          edges[i].cap -= x;
          edges[i ^ 1].cap += x;
          return x;
        }
      }
    }
    return 0;
  }
  void step() {
    for (int i = 1; i <= n; i++) {
      level[i] = -1;
      pos[i] = head[i];
    }
    level[1] = 0;
    queue<int> q;
    q.push(1);
    while (!q.empty()) {
      int a = q.front();
      q.pop();
      int ind = head[a];
      while (ind != -1) {
        int b = edges[ind].to;
        if (edges[ind].cap > 0 && level[b] == -1) {
          level[b] = 1 + level[a];
          q.push(b);
        }
        ind = edges[ind].nxt;
      }
    }
  }
  int get() {
    int sol = 0;
    while (1) {
      step();
      if (level[n] == -1) {
        break;
      }
      while (1) {
        int x = dfs(1, INF);
        if (x == 0) {
          break;
        }
        sol += x;
      }
    }
    return sol;
  }
  void algo() {
    way1.clear();
    wayn.clear();
    way1.resize(n + 1, 0);
    wayn.resize(n + 1, 0);
    for (int no = 1; no <= n; no += n - 1) {
      for (int i = 1; i <= n; i++) {
        level[i] = -1;
      }
      level[no] = 0;
      queue<int> q;
      q.push(no);
      while (!q.empty()) {
        int a = q.front();
        q.pop();
        int ind = head[a];
        while (ind != -1) {
          int b = edges[ind].to;
          if (edges[ind].cap > 0 && level[b] == -1) {
            level[b] = 1 + level[a];
            q.push(b);
          }
          ind = edges[ind].nxt;
        }
      }
      if (no == 1) {
       // cout << 1 << " : ";
        for (int i = 1; i <= n; i++) {
          way1[i] = (level[i] != -1);
          if (way1[i]) {
           // cout << i << " ";
          }
        }
       // cout << "\n";
      } else {
        assert(no == n);
       // cout << n << " : ";
        for (int i = 1; i <= n; i++) {
          wayn[i] = (level[i] != -1);
          if (wayn[i]) {
            //cout << i << " ";
          }
        }
     //   cout << "\n";
      }

    }
  }
};

struct T {
  int a, b, c;
};

int main() {
  freopen ("critice.in", "r", stdin);
  freopen ("critice.out", "w", stdout);
  int n, m;
  scanf("%d %d", &n, &m);
  if (n == 1) {
    assert(0);
    return 0;
  }
  vector<T> e;
  for (int i = 1; i <= m; i++) {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    assert(a != b);
    e.push_back({a, b, c});
  }
  flow f;
  f.init(n);
  for (auto &it : e) {
    f.add(it.a, it.b, it.c);
  }
  ///cout << "flow = " << f.get() << "\n";
  int init = f.get();
  f.algo();
  vector<int> sol;
  int step = 0;
  for (int step = 1; step <= m; step++) {
    int i1 = 2 * (step - 1), i2 = i1 + 1;
    int x = e[step - 1].a, y = e[step - 1].b;
    if ((f.way1[x] && f.wayn[y] && f.edges[i1].cap == 0) || (f.way1[y] && f.wayn[x] && f.edges[i2].cap == 0)) {
      sol.push_back(step);
    }

  //  f.edges[i1].cap++;
  //  f.edges[i2].cap++;
   // if (f.get()) {
     // sol.push_back(step);
   // }
  }
  cout << (int) sol.size() << "\n";
  for (auto &i : sol) {
    cout << i << "\n";
  }
  return 0;
}