#include <fstream>
#include <vector>
#include <cstring>
#include <bitset>
#define nmax 1005
using namespace std;
ifstream in("critice.in");
ofstream out("critice.out");
vector <int> v[nmax];
bitset <nmax> uz,en;
int n,m,sol[nmax*10],nrsol;
int p,u,q[nmax],t[nmax];
int f[nmax][nmax],c[nmax][nmax];
int x1[nmax*10],y1[nmax*10];



int bfs() {

    int i,x,y;
    uz.reset();
    memset(q,0,sizeof(q));
    memset(t,0,sizeof(t));
    p=1;u=1;
    q[1]=1;uz[1]=1;
    while (p<=u) {
        x=q[p];
        for (i=0;i<v[x].size();i++) {
            y=v[x][i];
            if (uz[y]==0&&c[x][y]>f[x][y]) {
                t[y]=x;
                uz[y]=1;
                q[++u]=y;
            }
        }
        p++;
    }
    return uz[n];
}
int main()
{
    int i,j,x,y,z,p,u,minx;
    in>>n>>m;
    for (i=1;i<=m;i++) {
        in>>x>>y>>z;
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y]=z;
        c[y][x]=z;
        x1[i]=x;
        y1[i]=y;
    }
    while (bfs()) {
        for (i=0;i<v[n].size();i++) {
            x=v[n][i];
            if (uz[x]==0||c[x][n]<=f[x][n])
                continue;
            minx=1<<30;
            t[n]=v[n][i];
            x=n;
            while (t[x]) {
                minx=min(minx,c[t[x]][x]-f[t[x]][x]);
                x=t[x];
            }
            if (minx==0)
                continue;
            x=n;
            while (t[x]) {
                f[t[x]][x]+=minx;
                f[x][t[x]]-=minx;
                x=t[x];
            }
        }
    }

    memset(q,0,sizeof(q));
    p=1;u=1;
    en[n]=1;
    q[1]=n;
    while (p<=u) {
        x=q[p];
        for (i=0;i<v[x].size();i++) {
            y=v[x][i];
            if (en[y]==0&&-f[x][y]<c[x][y]) {
                en[y]=1;
                q[++u]=y;
            }
        }
        p++;
    }
    for (i=1;i<=m;i++)
        if ((uz[x1[i]]&&en[y1[i]])||(uz[y1[i]]&&en[x1[i]]))
            sol[++nrsol]=i;
    out<<nrsol<<'\n';
    for (i=1;i<=nrsol;i++)
        out<<sol[i]<<'\n';
    return 0;
}