#include <fstream>
#include <vector>
#define DIM 1001
#define inf 2000000000
using namespace std;
ifstream fin("critice.in");
ofstream fout("critice.out");
int n,m,i,mini,ve,a,b,cap, sol[DIM],nod,j,va[10001],vb[10001],nr;
int c[DIM][DIM], f[DIM][DIM];
int d[DIM], z[DIM], t[DIM];
vector<int> v[DIM];

int bfs()
{
    int p=1, u=1, i, nod,vecin;
    for(i=1;i<=n;i++)
        d[i]=0;
    z[1]=1;
    d[1]=1;
    while(p<=u)
    {
        nod=z[p];
        for(i=0;i<v[nod].size();i++)
        {
            vecin=v[nod][i];
            if(c[nod][vecin]>f[nod][vecin]&&d[vecin]==0)
            {
                u++;
                z[u]=vecin;
                d[vecin]=1;
                t[vecin]=nod;
            }
        }
        p++;
    }
    return d[n];
}

void solve(int start, int val)
{
    int p=1, u=1, i, nod,vecin;
    for(i=1;i<=n;i++)
        d[i]=0;
    z[1]=start;
    d[start]=1;
    while(p<=u)
    {
        nod=z[p];
        for(i=0;i<v[nod].size();i++)
        {
            vecin=v[nod][i];
            if(f[nod][vecin]==0&&d[vecin]==0)
            {
                u++;
                z[u]=vecin;
                d[vecin]=1;
            }
        }
        p++;
    }
    for(i=1;i<=n;i++)
        if(d[i])
            sol[i]+=val;
}

int main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>a>>b>>cap;
        va[i]=a;vb[i]=b;
        v[a].push_back(b);
        v[b].push_back(a);
        c[a][b]=cap;
        c[b][a]=cap;
    }
    while(bfs()==1)
     {
        mini=inf;nod=n;
        while(t[nod])
        {
            mini=min(mini,c[t[nod]][nod]-f[t[nod]][nod]);
            nod=t[nod];
        }
        nod=n;
        while(t[nod])
        {
            f[t[nod]][nod]+=mini;
            f[nod][t[nod]]-=mini;
            nod=t[nod];
        }
    }
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
            if(f[i][j]==c[i][j]&&f[i][j])
            {
                f[i][j]=f[j][i]=1;
                c[i][j]=c[j][i]=1;
            }
            else
            {
                f[i][j]=f[j][i]=0;
                c[i][j]=c[j][i]=0;
            }
    solve(1, 1);solve(n, 2);
    for(int x=1;x<=m;x++)
    {
        i=va[x];j=vb[x];
        if(f[i][j]==1&&((sol[i]==1&&sol[j]==2)||(sol[i]==2&&sol[j]==1)))
            nr++;
    }
    fout<<nr<<"\n";
    for(int x=1;x<=m;x++)
    {
        i=va[x];j=vb[x];
        if(f[i][j]==1&&((sol[i]==1&&sol[j]==2)||(sol[i]==2&&sol[j]==1)))
            fout<<x<<"\n";
    }
    return 0;
}