#include <cstdio>
#include <vector>
#include <queue>
#define nmax 1001
#include <cstring>
#define inf 0x3f3f3f3f
#include <algorithm>

using namespace std;

int N,M,F[nmax][nmax],cap[nmax][nmax],cd[nmax],pred[nmax];
vector <int> G[nmax],R;
vector <pair<int,int> > T;
bool viz[nmax],source[nmax],dest[nmax];
queue <int> Q;

void BFS2(int s,bool vec[]){

  memset(viz,0,sizeof(viz));
  viz[s] = 1;
  Q.push(s);

  int x;
  vec[s] = 1;
  while(!Q.empty()){
    x = Q.front();
    Q.pop();
    for(vector <int> :: iterator v = G[x].begin();v != G[x].end();++v)
      if(viz[*v] == 0){
	if(F[x][*v] == cap[x][*v])
	  vec[x] = 1;
	else{
	  Q.push(*v);
	  viz[*v] = 1;
	}
      }
  }
  
}

bool BFS1(){

  memset(viz,0,sizeof(viz));
  viz[1] = 0;
  cd[0] = cd[1] = 1;

  for(int i = 1;i <= cd[0];i++){
    if(cd[i] != N){

      for(vector <int> :: iterator v = G[cd[i]].begin();v != G[cd[i]].end();++v){
	if(viz[*v] == 0 && F[cd[i]][*v] < cap[cd[i]][*v]){
	  viz[*v] = 1;
	  pred[*v] = cd[i];
	  cd[++cd[0]] = *v;
	}
      }
      
    }
  }

  return viz[N];
  
}

int main(){

  freopen("critice.in","r",stdin);
  freopen("critice.out","w",stdout);

  scanf("%d %d ",&N,&M);
  int x,y,z,i;

  for(i = 1;i <= M;i++){
    scanf("%d %d %d ",&x,&y,&z);
    G[x].push_back(y);
    G[y].push_back(x);
    cap[x][y] = cap[y][x] = z;
    T.push_back(make_pair(x,y));
  }

  int flow1 = 0,fmin;

  while(BFS1()){
    for(vector <int> :: iterator v = G[N].begin();v != G[N].end();++v){

      if(F[*v][N] == cap[*v][N] || viz[*v] == 0)continue;

      pred[N] = *v;
      
      fmin = inf;
      for(i = N;i != 1;i = pred[i])
	fmin = min(fmin,cap[pred[i]][i] - F[pred[i]][i]);

      if(fmin == 0)continue;

      for(i = N;i != 1;i = pred[i]){
	F[pred[i]][i] += fmin;
	F[i][pred[i]] += fmin;
      }

      flow1 += fmin;
      
    }
  }

  BFS2(1,source);
  BFS2(N,dest);

  //for(i = 1;i <= N;i++)printf("%d %d\n",source[i],dest[i]);

  for(i = 0;i < T.size();++i){
    if((source[T[i].first] == 1 && dest[T[i].second] == 1) || (source[T[i].second] == 1 && dest[T[i].first] == 1))
      R.push_back(i+1);
  }

  printf("%d\n",R.size());
  for(vector <int> :: iterator v = R.begin();v != R.end();++v)printf("%d\n",*v);
  
  return 0;
  
}