#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
const int NMAX = 1001;
const int MMAX = 50001;
struct muchie {
	int x,y;
};
vector <int> v[NMAX];
muchie a[MMAX];
int sol[MMAX];
int capacity[NMAX][NMAX],flux[NMAX][NMAX],p[NMAX],viz[NMAX],c[NMAX],n;
int bfs()
{
	int st,dr,x;
	st=1;
	dr=1;
	c[st]=1;
	memset(viz,0,sizeof(viz));
	viz[1]=1;
	while(st<=dr) {
		x=c[st];
		st++;
		for(vector <int> :: iterator it=v[x].begin();it!=v[x].end();it++) 
			if(viz[*it]==0 && capacity[x][*it]>flux[x][*it]) {
				viz[*it]=1;
				c[++dr]=*it;
				p[*it]=x;
				if(*it==n)
					return 1;
			}
	}
	return 0;
}
inline int saturata(int x, int y)
{
	if(max(flux[x][y],flux[y][x])==capacity[x][y])
		return 1;
	return 0;
}
int bfs2(int x, int y)
{
	int st,dr;
	if(x==y)
		return 1;
	st=1;
	dr=1;
	c[st]=x;
	memset(viz,0,sizeof(viz));
	viz[x]=1;
	while(st<=dr) {
		x=c[st];
		st++;
		for(vector <int> :: iterator it=v[x].begin();it!=v[x].end();it++) 
			if(viz[*it]==0 && saturata(x,*it)==0) {
				viz[*it]=1;
				c[++dr]=*it;
				if(*it==y)
					return 1;
			}
	}
	return 0;
}
int drum(int x, int y)
{
	if( ( bfs2(1,x) && bfs2(y,n) ) || ( bfs2(1,y) && bfs2(x,n) ) )
		return 1;
	return 0;
}
int main ()
{
	int i,x,y,m,cc,fluxmax,fluxcurent,nod;
	ifstream f("critice.in");
	ofstream g("critice.out");
	f>>n>>m;
	for(i=1;i<=m;i++) {
		f>>x>>y>>cc;
		v[x].push_back(y);
		v[y].push_back(x);
		capacity[x][y]=cc;
		capacity[y][x]=cc;
		a[i].x=x;
		a[i].y=y;
	}
	f.close();
	for(fluxmax=0 ; bfs(); fluxmax=fluxmax+fluxcurent) {
		fluxcurent=(1<<30);
		for(nod=n;nod!=1;nod=p[nod])
			fluxcurent=min(fluxcurent,capacity[p[nod]][nod]-flux[p[nod]][nod]);
		for(nod=n;nod!=1;nod=p[nod]) {
			flux[p[nod]][nod]=flux[p[nod]][nod]+fluxcurent;
			flux[nod][p[nod]]=flux[nod][p[nod]]-fluxcurent;
		}
	}
	for(i=1;i<=m;i++)
		if(saturata(a[i].x,a[i].y)) {
			if(drum(a[i].x,a[i].y)==1) 
				sol[++sol[0]]=i;
		}
	g<<sol[0]<<'\n';
	for(i=1;i<=sol[0];i++)
		g<<sol[i]<<'\n';
	g.close();
	return 0;
}