#include <bits/stdc++.h>
using namespace std;
const int N = 12505;
const int M = 1000005;
int n, m, w[N], a[N], b[M], eu[M], ev[M];
bool vis[M * 2];
vector<pair<int, int> > G[N];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    G[u].emplace_back(v, i);
    G[v].emplace_back(u, i);
    b[i] = 1;
    eu[i] = u, ev[i] = v;
  }
  for (int i = 1; i <= n; i++) w[i] = (int)G[i].size(), a[i] = 0;
  for (int u = 1; u <= n; u++) {
    int sz = 0;
    for (auto &e : G[u]) {
      int v = e.first, id = e.second;
      if (v > u) continue;
      sz++;
      if (a[v]) {
        a[v]--;
        b[id]++;
        w[u]++;
      }
    }
    int x;
    for (x = w[u] - sz; x <= w[u]; x++) vis[x] = 0;
    for (auto &e : G[u]) {
      int v = e.first;
      if (v > u) continue;
      vis[w[v]] = 1;
    }
    for (x = w[u] - sz; x <= w[u]; x++)
      if (!vis[x]) break;
    x = w[u] - x;
    for (auto &e : G[u]) {
      if (!x) break;
      int v = e.first, id = e.second;
      if (v > u) continue;
      x--;
      a[v]++;
      b[id]--;
      w[u]--;
    }
  }
  int cc = 0;
  for (int i = 1; i <= n; i++)
    if (a[i]) cc++;
  printf("%d\n", cc);
  for (int i = 1; i <= n; i++)
    if (a[i]) printf("%d\n", i);
  for (int i = 1; i <= m; i++) printf("%d %d %d\n", eu[i], ev[i], b[i]);
  return 0;
}
