#include<fstream>
#include<vector>
#include<queue>
#include<cstring>
#include<algorithm>
#define inf 1<<30
using namespace std;
ofstream g("critice.out");
int n,m,i,j,C[1003][1003],t[1003],z,nod,fluxct,nr;
vector<int>a[1003],b;
queue<int>q;
bool uz[1001];
long long fluxmax;
struct muchie
{
    int x,y;
};
muchie M[100001];
inline int bf()
{
    int i,x;
    memset(uz,0,sizeof(uz));
    q.push(1);
    uz[1]=1;
    while(!q.empty())
    {
        x=q.front();
        if(x!=n)
        {
            for(i=0;i<a[x].size();++i)
            if(!uz[a[x][i]]&&C[x][a[x][i]])
            {
                uz[a[x][i]]=1;
                t[a[x][i]]=x;
                q.push(a[x][i]);
            }
        }
        q.pop();
    }
    return uz[n];
}
inline int bf2(int x)
{
    int i,xi;
    xi=x;
    q.push(x);
    uz[x]=1;
    t[x]=x;
    while(!q.empty())
    {
        x=q.front();
        for(i=0;i<a[x].size();++i)
        if(!uz[a[x][i]]&&C[a[x][i]][x])
        {
            uz[a[x][i]]=1;
            t[a[x][i]]=t[x];
            q.push(a[x][i]);
        }
        q.pop();
    }

}
int main()
{
    ifstream f("critice.in");
    f>>n>>m;
    for(i=1;i<=m;++i)
    {
        f>>M[i].x>>M[i].y>>z;
        a[M[i].x].push_back(M[i].y);
        a[M[i].y].push_back(M[i].x);
        C[M[i].x][M[i].y] = C[M[i].y][M[i].x] =z;

    }
    fluxmax=0;
    while(bf())
    {
        for(i=0;i<a[n].size();++i)
        if(uz[a[n][i]]&&C[ a[n][i] ][n]>0 )
        {
            t[n]=a[n][i];
            fluxct=inf;
            for(nod=n;nod!=1;nod=t[nod])
            fluxct=min(fluxct,C[t[nod]][nod]);

            if(fluxct)
            {

                for(nod=n;nod!=1;nod=t[nod])
                {
                    C[t[nod]][nod]-=fluxct;
                    C[nod][t[nod]]-=fluxct;
                }
                fluxmax+=fluxct;
            }
        }
    }
    memset(t,0,sizeof(t));
    memset(uz,0,sizeof(uz));
    bf2(1);
    bf2(n);

    for(i=1;i<=m;++i)
    if(C[M[i].x][M[i].y]==0&&(t[M[i].x]==n&&t[M[i].y]==1||t[M[i].x]==1&&t[M[i].y]==n))
    ++nr,b.push_back(i);

    g<<nr<<'\n';
    for(i=0;i<nr;++i)
    g<<b[i]<<'\n';
}