#include <bits/stdc++.h>
using namespace std;
int m,n,x[10010],y[10010],c[1010][1010],i,cst,t[1010],nr,f[1010][1010];
bool ap[5][1010],ok;
vector<int>v[1010],ter,ans;
queue<int>q;
void del()
{
    vector<int>aa;
    aa.swap(ter);
}
bool bsf()
{
    q.push(1);
    t[1]=-1;
    ok=false;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        for(auto &it: v[nod])
        {

            if (t[it] || c[nod][it] == f[nod][it]) continue;
            if(it==n)
            {
                ter.push_back(nod);
                ok=true;
                continue;
            }
            t[it]=nod;
            q.push(it);
        }
    }
    return ok;
}
void dsf(int nod,int mrk)
{
    ap[mrk][nod]=true;
    for(auto &it:v[nod])
        if(!ap[mrk][it]&&((!mrk&&c[nod][it]>f[nod][it])||(mrk&&c[it][nod]>f[it][nod])))dsf(it,mrk);
}
int main()
{
    freopen("critice.in","r",stdin);
    freopen("critice.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1; i<=m; ++i)
    {
        scanf("%d%d%d",&x[i],&y[i],&cst);
        v[x[i]].push_back(y[i]);
        v[y[i]].push_back(x[i]);
        c[x[i]][y[i]]=cst;
        c[y[i]][x[i]]=cst;
    }
    while(bsf())
    {
        for(auto &it: ter)
        {
            t[n]=it;
            int  nod=n;
            int  mi=INT_MAX;
            while(t[nod]!=-1)
            {
                mi=min(mi,c[t[nod]][nod]-f[t[nod]][nod]);
                nod=t[nod];
            }
            nod=n;
            while(t[nod]!=-1)
            {
                f[nod][t[nod]]-=mi;
                f[t[nod]][nod]+=mi;
                nod=t[nod];
            }
        }
        del();
        for(i=1; i<=n; ++i)
            t[i]=0;
    }
    dsf(1,0);
    dsf(n,1);
    for(i=1; i<=m; ++i)
        if((f[x[i]][y[i]]==c[x[i]][y[i]]||f[y[i]][x[i]]==c[y[i]][x[i]])&&((ap[0][x[i]]&&ap[1][y[i]])||(ap[1][x[i]]&&ap[0][y[i]])))++nr,ans.push_back(i);
    printf("%d\n",nr);
    for(auto &it:ans)
    {
        printf("%d\n",it);
    }
    return 0;
}