#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 <pair<int,int> > G[nmax];
vector <int> R;
bool viz[nmax],source[nmax],dest[nmax];

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

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

  vec[s] = 1;
  for(int i = 1;i <= cd[0];i++){
    for(vector <pair<int,int> > :: iterator it = G[cd[i]].begin();it != G[cd[i]].end();++it)
      if(viz[it->first] == 0){
	if(F[cd[i]][it->first] == cap[cd[i]][it->first]){
	  if(vec[cd[i]] == 0)vec[cd[i]] = 1;
	  if(ok && source[it->first] == 1)R.push_back(it->second);
	}
	else{
	  cd[++cd[0]] = it->first;
	  viz[it->first] = 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 <pair<int,int> > :: iterator v = G[cd[i]].begin();v != G[cd[i]].end();++v){
	if(viz[v->first] == 0 && F[cd[i]][v->first] < cap[cd[i]][v->first]){
	  viz[v->first] = 1;
	  pred[v->first] = cd[i];
	  cd[++cd[0]] = v->first;
	}
      }
      
    }
  }

  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(make_pair(y,i));
    G[y].push_back(make_pair(x,i));
    cap[x][y] = cap[y][x] = z;
  }

  int flow1 = 0,fmin;

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

      if(F[v->first][N] == cap[v->first][N] || viz[v->first] == 0)continue;

      pred[N] = v->first;
      
      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,0);
  BFS2(N,dest,1);

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

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