#include<stdio.h>
#include<vector>
using namespace std;
FILE*f=fopen("critice.in","r");
FILE*g=fopen("critice.out","w");
int m,n,nr,x,y,z,minn,p,u,ok1,ok2,ok3,ok4,c[1001][1001],F[1001][1001],sol[10001],t[1001],d[1003];
char viz[1001],s1[1001],s2[1001];
struct tunele
{
	int x,y;
}M[10001];
vector <int> v[1001];
int bfs()
{
	d[1]=p=u=1;
	int ok=0;
	
	for(int i=1;i<=n;++i)
		viz[i]=0;
	while(p<=u)
	{
		int nod=d[p];
		for(int i=0;i<v[nod].size();++i)
			if(!viz[v[nod][i]]&&c[nod][v[nod][i]]-F[nod][v[nod][i]]>0)
			{
				if(v[nod][i]!=n)
				{
					t[v[nod][i]]=nod;
					d[++u]=v[nod][i];
					viz[v[nod][i]]=1;
				}
				else
					ok=1;
			}
		++p;
	}
	return ok;
}
int intreg(int x)
{
	if(x<0)
		return -x;
	return x;
}
void bfs2(int nod,char s[])
{
	p=u=1;
	d[p]=nod;
	for(int i=1;i<=n;++i)
		viz[i]=0;
	if(nod==1)
		ok1=1;
	else if(nod==n)
		ok2=1;
	while(p<=u)
	{
		int nod=d[p];
		for(int i=0;i<v[nod].size();++i)
			if(!s[v[nod][i]]&&c[nod][v[nod][i]]-intreg(F[nod][v[nod][i]])>0)
			{
				if(v[nod][i]!=n&&v[nod][i]!=1)
				{
					d[++u]=v[nod][i];
					s[v[nod][i]]=1;
				}
				
			}
		++p;
	}
	
}
int main()
{
	fscanf(f,"%d%d",&n,&m);
	for(int i=1;i<=m;++i)
	{
		fscanf(f,"%d%d%d",&x,&y,&z);
		M[i].x=x;
		M[i].y=y;
		v[x].push_back (y);
		v[y].push_back (x);
		c[x][y]=c[y][x]=z;
	}
	
	while(bfs())
	{
		for(int i=0;i<v[n].size();++i)
		{
			minn=c[v[n][i]][n]-F[v[n][i]][n];
			
			for(int nod=v[n][i];nod!=1;nod=t[nod])
				if(minn>c[t[nod]][nod]-F[t[nod]][nod])
					minn=c[t[nod]][nod]-F[t[nod]][nod];
				
			F[v[n][i]][n]+=minn;
			F[n][v[n][i]]-=minn;
			
			for(int nod=v[n][i];nod!=1;nod=t[nod])
			{
				F[t[nod]][nod]+=minn;
				F[nod][t[nod]]-=minn;
			}
		}
	}	
	
	bfs2(1,s1);
	bfs2(n,s2);
	s1[1]=1;
	s2[n]=1;
	for(int ii=1;ii<=m;++ii){
		x=M[ii].x;
		y=M[ii].y;
		if((F[x][y]==c[x][y]||F[y][x]==c[y][x])&&((s1[x]&&s2[y])||(s2[x]&&s1[y])))
		{
			++nr;
			sol[nr]=ii;
		}
	}
	fprintf(g,"%d\n",nr);
	for(int i=1;i<=nr;++i)
		fprintf(g,"%d\n",sol[i]);
	
	fclose(g);
	fclose(f);
	return 0;
}