//http://infoarena.ro/problema/critice -> rezolvarea :  fac flux si verific dupa aceea cu doua parcurgeri din cele doua capete care muchii sunt saturate si se vad extremitatzile ei din ambele parti

using namespace std;

#include <cstdio>
#include <cassert>

#define FIN "critice.in"
#define FOUT "critice.out"
#define NMAX 1001
#define MMAX 10001
#define INF 0x3f3f3f3f

int c[NMAX][NMAX], N, M, f[NMAX][NMAX], iter, vizs[NMAX], vizt[NMAX];
int pred[NMAX], d[NMAX], rez[MMAX], cd[NMAX], begin, ended;
int retn1[MMAX], retn2[MMAX];
struct nod {int vf, inf;
            nod *next;};
typedef nod *pnod;
pnod a[NMAX];

void add (int x, int y, int z)
{
  pnod p = new nod;
  p -> vf = y;
  p -> inf = z;
  p -> next = a[x];
  a[x] = p;
}

void bf ()
{
  int v, i;
  pnod p;
  d[1] = iter;
  begin  = ended = 0;
  cd[ended++] = 1;
  while (begin != ended)
   {
     v = cd[begin++];
     assert (v >= 1 && v <= N);
     for (p = a[v]; p; p = p -> next)
      {
        i = p -> vf;
        if (c[v][i] - f[v][i] > 0 && d[i] != iter)
         {
           d[i] = iter;
           pred[i] = v;
           cd[ended++] = i;
           if (i == N)
            return;
         }
      }
   }
}

void ford_fulk ()
{
  int i, min;
  ++ iter;
  while (d[N] != iter)
   {
     min = INF;
     bf ();
     if (d[N] != iter)
       break;
     i = N;
     while (pred[i])
      {
        if (min > c[pred[i]][i] - f[pred[i]][i])
          min = c[pred[i]][i] - f[pred[i]][i];
        i = pred[i];
      }
     i = N;
     while (pred[i])
      {
        f[pred[i]][i] += min;
        f[i][pred[i]] -= min;
        i = pred[i];
      }
     ++ iter;
   }
}

void bfs ()
{
  ++ iter;
  int v;
  d[1] = iter;
  vizs[1] = true;
  begin = ended = 0;
  cd[ended++] = 1;
  while (begin != ended)
   {
     v = cd[begin++];
     //fprintf (stderr, "%d ", v);
     assert (v >= 1 && v <= N);
     for (int i = 1; i <= N; ++ i)
       if (c[v][i] - f[v][i] > 0 && d[i] != iter && -f[v][i] != c[v][i])
        {
          d[i] = iter;
          vizs[i] = true;
          cd[ended++] = i;
        }
   }
}

void bft ()
{
  ++ iter;
  int v;
  d[N] = iter;
  vizt[N] = true;
  begin = ended = 0;
  cd[ended++] = N;
  while (begin != ended)
   {
     v = cd[begin++];
     //fprintf (stderr, "%d ", v);
     assert (v >= 1 && v <= N);
     for (int i = 1; i <= N; ++ i)
       if (c[v][i] - f[v][i] > 0 && d[i] != iter && -f[v][i] != c[v][i])
        {
          d[i] = iter;
          vizt[i] = true;
          cd[ended++] = i;
        }
   }
}

int
 main ()
{
  int x, y, cap;
  freopen (FIN, "rt", stdin);
  freopen (FOUT, "wt", stdout);

  scanf ("%d%d", &N, &M);
  for (int i = 1; i <= M; ++ i)
   {
     scanf ("%d%d%d", &x, &y, &cap);
     c[x][y] = c[y][x] = cap;
     add (x, y, cap);
     add (y, x, cap);
     retn1[i] = x;
     retn2[i] = y;
   }
  ford_fulk ();
  bfs ();
  bft ();
  int ct = 0;
  for (int i = 1; i <= M; ++ i)
    if ((vizs[retn1[i]] && vizt[retn2[i]]) ||     
         (vizs[retn2[i]] && vizt[retn1[i]]))
           rez[++ct] = i;
  printf ("%d\n", ct);
  for (int i = 1; i <= ct; ++ i)
    printf ("%d\n", rez[i]);
  return 0;
}