#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

const int NMAX = 1000;
const int MMAX = 10000;
const int INF = 1000000000;

struct muchie {
  int inc, sf, cf; /// nod de inceput, sfarsit, si cf = capacitate - flux

  muchie(int iinc = 0, int ssf = 0, int ccf = 0) {
    inc = iinc, sf = ssf, cf = ccf;
  }
};

bool uz[NMAX + 5], uz_1n[NMAX + 5], uz_n1[NMAX + 5];
int n, m;
int from[NMAX + 5];
muchie muchii[2 * MMAX + 5];
vector<int> v[NMAX + 5];
queue<int> q;

bool bfs(int start) {
  for(int i = 1; i <= n; i++)
    uz[i] = false, from[i] = -1;
  q.push(start);
  uz[start] = true;

  while(!q.empty()) {
    int nod = q.front();
    q.pop();
    if(nod == n)
      continue;

    for(int x: v[nod]) {
      int vec = muchii[x].sf, cf = muchii[x].cf;

      if(!uz[vec] && cf > 0) {
        from[vec] = x;
        q.push(vec);
        uz[vec] = true;
      }
    }
  }

  return uz[n];
}

void update_flux() {
  int minf = INF;
  for(int i = n; from[i] != -1; i = muchii[from[i]].inc)
    minf = min(minf, muchii[from[i]].cf);
  if(minf == 0)
    return;

  for(int i = n; from[i] != -1; i = muchii[from[i]].inc) {
    muchii[from[i]].cf -= minf; /// adaug flux in sensul drumului de ameliorare
    muchii[from[i] ^ 1].cf += minf; /// si scad in sens invers
  }
}

void flux() {
  while(bfs(1)) /// cat timp gasesc drum de ameliorare din 1 pana in n
    for(int x: v[n]) {
      int nod = muchii[x].sf, cf = muchii[x ^ 1].cf; /// x ^ 1 -> muchie inversa

      if(uz[nod] && cf > 0) {
        from[n] = x ^ 1;
        update_flux();
      }
    }
}

void bfs2(int start, int dest, bool *uz2) {
  int xr = (start == 1) ? 0 : 1;
  q.push(start);
  uz2[start] = true;

  while(!q.empty()) {
    int nod = q.front();
    q.pop();
    if(nod == dest)
      continue;

    for(int x: v[nod]) {
      int vec = muchii[x].sf, cf = muchii[x ^ xr].cf;
      if(!uz2[vec] && cf > 0) {
        q.push(vec);
        uz2[vec] = true;
      }
    }
  }
}

int main() {
  freopen("critice.in", "r", stdin);
  freopen("critice.out", "w", stdout);
  int x, y, z;

  scanf("%d %d", &n, &m);
  for(int i = 0; i < m; i++) {
    scanf("%d %d %d", &x, &y, &z);
    muchii[2 * i] = muchie(x, y, z);
    muchii[2 * i + 1] = muchie(y, x, z);
    v[x].push_back(2 * i);
    v[y].push_back(2 * i + 1);
  }

  flux();
  bfs2(1, n, uz_1n); /// bfs de la sursa la destinatie
  bfs2(n, 1, uz_n1); /// bfs de la destinatie la sursa

  int nr_critice = 0;
  for(int i = 0; i < m; i++) {
    int nod1 = muchii[2 * i].inc, nod2 = muchii[2 * i].sf;
    if((uz_1n[nod1] && uz_n1[nod2]) || (uz_1n[nod2] && uz_n1[nod1]))
      nr_critice++;
  }
  printf("%d\n", nr_critice);
  for(int i = 0; i < m; i++) {
    int nod1 = muchii[2 * i].inc, nod2 = muchii[2 * i].sf;
    if((uz_1n[nod1] && uz_n1[nod2]) || (uz_1n[nod2] && uz_n1[nod1]))
      printf("%d\n", i + 1);
  }

  return 0;
}