#include <fstream>
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fi("critice.in");
ofstream fo("critice.out");
 
int i,j,n,m,c[1001][1001],cr[1001][1001],viz[1001],cd[10001],f[1001][1001],t[1001],flux,s1[1001],s2[1001];
vector< int >rsa,g[1001];
struct muchie{int x,y;}v[10001];
 
int BFS()
{
    for (int i=1; i<=n; i++) viz[i]=0;
    int st=1,dr=1;
    cd[1]=1;
    while (st<=dr)
    {
        int nod=cd[st++];
        for (int i=1; i<=n; i++)
        {
            if (c[nod][i]>f[nod][i] && !viz[i])
            {
                viz[i]=1;
                t[i]=nod;
                cd[++dr]=i;
            }
        }
    }
    return viz[n];
}

void bfs(int nod,int a[])
{
	for (i=1; i<=n; i++) viz[i]=0;
	int st=1,dr=1;
	cd[1]=nod;
	while (st<=dr)
	{
		int nod=cd[st++];
		for (size_t k=0; k<g[nod].size(); k++)
		{
			int u=g[nod][k];
			if (!a[u] && c[nod][u]>f[nod][u])
			{
				if (u!=n && u!=1)
				{
					cd[++dr]=u;
					viz[u]=1;
					a[u]=1;
				}
			}
		}
	}
}

int fl()
{
    int flux=0;
    for (i=1; i<=n; i++)
        for(j=1; j<=n; j++)
            f[i][j]=0;
    while (BFS())
    {
        for (i=1; i<=n; i++)
        {
            if (c[i][n]>f[i][n])
            {
                int fmin=c[i][n]-f[i][n];
                for (j=i; j!=1; j=t[j])
                    fmin=min(fmin,c[t[j]][j]-f[t[j]][j]);
                for (j=i; j!=1; j=t[j])
                {
                    f[t[j]][j]+=fmin;
                    f[j][t[j]]-=fmin;
                }
                f[i][n]+=fmin;
                f[n][i]-=fmin;
                flux+=fmin;
            }
        }
    }
    return flux;
}
 
int main(){
     
    fi >> n >> m;
    for (i=1; i<=m; i++)
    {
        int x,y,z;
        fi >> x >> y >> z;
        v[i].x=x; v[i].y=y;
        g[x].push_back(y);
        g[y].push_back(x);
        c[x][y]=c[y][x]=z;
    }
     
    fl();
     
	bfs(1,s1); bfs(n,s2);
    s1[1]=1;
    s2[n]=1;
    for (i=1; i<=m; i++)
    {
		int x=v[i].x,y=v[i].y;
		if (((s1[x]&&s2[y])||(s1[y]&&s2[x]))&&((c[x][y]==f[x][y])||(c[y][x]==f[y][x]))) rsa.push_back(i);
	}
	
	fo << rsa.size() << endl;
	for (size_t k=0; k<rsa.size(); k++)
		fo << rsa[k] << endl;
     
    return 0;
}