#include <bits/stdc++.h>
#define pb push_back
using namespace std;
ifstream fi("critice.in");
ofstream fo("critice.out");

const int NMAX = 1005;
const int INF = (1e9);

int n, m;
vector <int> G[NMAX];
int C[NMAX][NMAX], F[NMAX][NMAX];
int cnt[NMAX][NMAX];
int p[NMAX];
bool viz[NMAX];
queue <int> Q;
vector <int> rez, rez2;
pair <int, int> much[NMAX];
bool drum[2][1005];

void dfsVerificare(int nod, int sef)
{
   drum[sef][nod] = 1;
   viz[nod] = 1;
   for (auto v: G[nod])
   {
      if (!viz[v] && F[nod][v] != C[nod][v] && F[v][nod] != C[v][nod])
      {
         dfsVerificare(v, sef);
      }
   }
}

int bfs()
{
    memset(viz, 0, sizeof(viz));
    memset(p, 0, sizeof(p));

    Q.push(1);
    viz[1] = 1;

    while (!Q.empty())
    {
        int curr = Q.front();
        Q.pop();

        if (curr == n)
            continue;

        for (auto v: G[curr])
        {
            if (F[curr][v] == C[curr][v] || viz[v])
                continue;

            Q.push(v);
            viz[v] = 1;
            p[v] = curr;
        }
    }
    return viz[n];
}

int main()
{
    fi >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int u, v, c;
        fi >> u >> v >> c;
        G[u].pb(v);
        G[v].pb(u);
        C[u][v] = C[v][u] = c;
        cnt[u][v] = cnt[v][u] = i;
        much[i] = {u, v};
    }

    int flow = 0;

    while (bfs())
        for (auto v: G[n])
        {
            if (F[v][n] == C[v][n] || !viz[v])
                continue;

            int minim = INF, poz = -1;
            for (int nod = n; nod != 1; nod = p[nod])
            {
                if (C[p[nod]][nod] - F[p[nod]][nod] < minim)
                {
                    minim = C[p[nod]][nod] - F[p[nod]][nod];
                    poz = cnt[p[nod]][nod];
                }
                else if (C[p[nod]][nod] - F[p[nod]][nod] == minim)
                    poz = -1;

                minim = min(minim, C[p[nod]][nod] - F[p[nod]][nod]);
            }

            for (int nod = n; nod != 1; nod = p[nod])
            {
                F[p[nod]][nod] += minim;
                F[nod][p[nod]] -= minim;
            }

            if (poz != -1)
                rez.pb(poz);

            flow += minim;
        }

    memset(viz, 0, sizeof(viz));
    dfsVerificare(1, 0);
    memset(viz, 0, sizeof(viz));
    dfsVerificare(n, 1);

    for (auto x: rez)
    {
       if ((drum[0][much[x].first] && drum[1][much[x].second])
          || (drum[1][much[x].first] && drum[0][much[x].second]))
          rez2.pb(x);
    }


    fo << rez2.size() << "\n";
    for (auto x: rez2)
        fo << x << "\n";

    return 0;
}