#include<cstdio>
#include<cstring>
#include<queue>
#include<vector>
#define inf 10000000
#define NMax 1005
using namespace std;

int C[NMax][NMax],N,tata[NMax];
int F[NMax][NMax],viz[NMax];
int rch[2][NMax];
queue<int> Q;
vector<int> V[NMax],sol;
vector<pair<int,int> > Mc;

int BF ()
{
    int fiu,crt,i;
    memset(viz,0,sizeof(viz));
    viz[1]=1;
    Q.push(1);
    while (!Q.empty())
    {
        crt=Q.front(), Q.pop();
        if (crt==N) continue;
        for (i=0; i<V[crt].size(); i++)
        {
            fiu=V[crt][i];
            if (viz[fiu] || C[crt][fiu]<=F[crt][fiu]) continue;
            Q.push(fiu);
            viz[fiu]=1;
            tata[fiu]=crt;
        }
    }
    return viz[N];
}

void DF (int nod, int tip)
{
    rch[tip][nod]=1;
    for (int i=0; i<V[nod].size(); i++)
    {
        int fiu=V[nod][i];
        if (C[nod][fiu]==F[nod][fiu]) continue;
        if (!rch[tip][fiu])
            DF(fiu,tip);
    }
}

int main ()
{
    int M,i,x,y,d,nod,pnm,min_flux;
    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,&y,&d);
        C[x][y]=C[y][x]=d;
        V[x].push_back(y);
        V[y].push_back(x);
        Mc.push_back(make_pair(x,y));
    }
    while (BF())
        for (i=0; i<V[N].size(); i++)
        {
            pnm=V[N][i], tata[N]=pnm;
            if (!viz[pnm]) continue;
            min_flux=inf;
            for (nod=N; nod!=1; nod=tata[nod])
                if (C[tata[nod]][nod]-F[tata[nod]][nod]<min_flux)
                    min_flux=C[tata[nod]][nod]-F[tata[nod]][nod];
            for (nod=N; nod!=1; nod=tata[nod])
            {
                F[tata[nod]][nod]+=min_flux;
                F[nod][tata[nod]]-=min_flux;
            }
        }
    DF(1,0);
    DF(N,1);
    for (i=0; i<M; i++)
    {
        x=Mc[i].first, y=Mc[i].second;
        if ((C[x][y]==F[x][y] && rch[0][x] && rch[1][y]) ||
            (C[y][x]==F[y][x] && rch[0][y] && rch[1][x]))
                sol.push_back(i);
    }
    printf("%d\n",sol.size());
    for (i=0; i<sol.size(); i++)
        printf("%d\n",sol[i]+1);
    return 0;
}