#include <cstdio>
#include <iostream>
#include <cstring>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;


#define maxN 1005
#define INF 0x3f3f3f
#define PB push_back


int N , M , cap[maxN][maxN] , flux[maxN][maxN];
int muchie[maxN][maxN] , fluxmax , tata[maxN];
bool viz[maxN];


vector <int> lista[maxN];
queue <int> Q;

int dim = 0 , sol[maxN];

int am_flux ()
{
	Q.push (1);
	
	memset (viz , 0 , sizeof (viz));
	
	viz[1] = true;
	
	
	while (!Q.empty ())
	{
		int nod = Q.front ();
		Q.pop ();
		
		
		for (unsigned int i = 0 ; i < lista[nod].size () ; ++i)
		{
			int nodcur = lista[nod][i];
			
			
			if (viz[nodcur])
				continue;
			
			if (cap[nod][nodcur] - flux[nod][nodcur] == 0)
				continue;
			
			Q.push (nodcur);
			viz[nodcur] = true;
			
			tata[nodcur] = nod;
			
		}
	}
	
	if (!viz[N])
		return 0;
	
	
	int minim = INF;
	
	for (int nod = N ; nod != 1 ; nod = tata[nod])
		minim = min (minim , cap[tata[nod]][nod] - flux[tata[nod]][nod]);
	
	for (int nod = N ; nod != 1 ; nod = tata[nod])
	{
		flux[tata[nod]][nod] += minim;
		flux[nod][tata[nod]] -= minim;
	}
	
	return 1;
}




int bfs1 (int start , int cap1 , int cap2)
{
	Q.push (start);
	
	memset (viz , 0 , sizeof (viz));
	
	viz[start] = true;
	
	
	while (!Q.empty ())
	{
		int nod = Q.front ();
		Q.pop ();
		
		
		if (nod == cap1 || nod == cap2)
			return nod;
		
		
		for (unsigned int i = 0 ; i < lista[nod].size () ; ++i)
		{
			int nodcur = lista[nod][i];
			
			if (viz[nodcur])
				continue;
			
			if (cap[nod][nodcur] > flux[nod][nodcur] && cap[nodcur][nod] > flux[nodcur][nod])
			{
				if (nodcur == cap1 || nodcur == cap2)
					return nod;
				
				Q.push (nodcur);
				viz[nodcur] = true;
			}
		}
	}
	
	return -1;
}


int bfs2 (int start , int finish)
{
	Q.push (start);
	
	memset (viz , 0 , sizeof (viz));
	
	viz[start] = true;
	
	
	while (!Q.empty ())
	{
		int nod = Q.front ();
		Q.pop ();
		
		if (nod == finish)
			return 1;
		
		for (unsigned int i = 0 ; i < lista[nod].size () ; ++i)
		{
			int nodcur = lista[nod][i];
			
			
			if (viz[nodcur])
				continue;
			
			if (cap[nod][nodcur] > flux[nod][nodcur] && cap[nodcur][nod] > flux[nodcur][nod])
			{
				if (nodcur == finish)
					return 1;
				
				Q.push (nodcur);
				viz[nodcur] = true;
			}
		}
	}
	
	return 0;
}



int main ()
{
	freopen ("critice.in" , "r" , stdin);
	freopen ("critice.out" , "w" , stdout);
	
	scanf ("%d %d" , &N , &M);
	
	
	int a , b , c;
	
	for (int i = 1 ; i <= M ; ++i)
	{
		scanf ("%d %d %d" , &a , &b , &c);
		
		lista[a].PB (b);
		lista[b].PB (a);
		
		cap[a][b] = c;
		cap[b][a] = c;
		
		
		muchie[a][b] = i;
		muchie[b][a] = i;
	}
	
	
	while (am_flux ());
	
	
	int aux;
	
	
	for (int nod = 1 ; nod <= N ; ++nod)
		for (unsigned int i = 0 ; i < lista[nod].size () ; ++i)
		{
			int nodcur = lista[nod][i];
			
			
			if (cap[nod][nodcur] - flux[nod][nodcur] != 0)
				continue;
			
			
			int rez = bfs1 (1 , nod , nodcur); //start , capat1 , capat2
			
			if (rez != nod && rez != nodcur) 
				continue;
			
			
			if (rez == nod)
				aux = N;
			
			else aux = nod;
			
			if (bfs2 (N , aux))
				sol[++dim] = muchie[nod][nodcur];
		}
	
	printf ("%d\n" , dim);
	
	sort (sol + 1 , sol + dim + 1);
	
	for (int i = 1 ; i <= dim ; ++i)
		printf ("%d\n" , sol[i]);
	
	
	return 0;
}