#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
#include <cstring>
#define nmax 1005
#define mmax 10005
using namespace std;
ifstream in("critice.in");
ofstream out("critice.out");
vector <int> v[nmax];
bitset <nmax> uz,en;
queue <int> q;
int n,m,sol[mmax],t[nmax],nrsol;
int f[nmax][nmax],c[nmax][nmax];
int x1[mmax],y1[mmax];

int bfs() {

    int i,x,y;
    uz.reset();
    memset(t,0,sizeof(t));
    q.push(1);
    uz[1]=1;
    while (!q.empty()) {
        x=q.front();
        q.pop();
        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.push(y);
            }
        }
    }
    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()) {
        minx=1<<30;
        for (i=n;i!=1;i=t[i])
            minx=min(minx,c[t[x]][x]-f[t[x]][x]);
        if (minx==0)
            continue;
        for (i=n;i!=1;i=t[i]) {
            f[t[i]][i]+=minx;
            f[i][t[i]]-=minx;
        }
    }
    q.push(n);
    en[n]=1;
    while (!q.empty()) {
        x=q.front();
        q.pop();
        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.push(y);
            }
        }
    }
    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;
}