#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
template <typename T>
void ckmn(T& a, T b) {
  a = min(a, b);
}
template <typename T>
void ckmx(T& a, T b) {
  a = max(a, b);
}
void rd(int& x) { scanf("%i", &x); }
void rd(long long& x) { scanf("%lld", &x); }
void rd(char* x) { scanf("%s", x); }
void rd(double& x) { scanf("%lf", &x); }
void rd(string& x) { scanf("%s", &x); }
template <typename T1, typename T2>
void rd(pair<T1, T2>& x) {
  rd(x.first);
  rd(x.second);
}
template <typename T>
void rd(vector<T>& x) {
  for (T& i : x) rd(i);
}
template <typename T, typename... A>
void rd(T& x, A&... args) {
  rd(x);
  rd(args...);
}
template <typename T>
void rd() {
  T x;
  rd(x);
  return x;
}
int ri() {
  int x;
  rd(x);
  return x;
}
template <typename T>
vector<T> rv(int n) {
  vector<T> x(n);
  rd(x);
  return x;
}
template <typename T>
void ra(T a[], int n, int st = 1) {
  for (int i = 0; i < n; ++i) rd(a[st + i]);
}
template <typename T1, typename T2>
void ra(T1 a[], T2 b[], int n, int st = 1) {
  for (int i = 0; i < n; ++i) rd(a[st + i]), rd(b[st + i]);
}
template <typename T1, typename T2, typename T3>
void ra(T1 a[], T2 b[], T3 c[], int n, int st = 1) {
  for (int i = 0; i < n; ++i) rd(a[st + i]), rd(b[st + i]), rd(c[st + i]);
}
void re(vector<int> E[], int m, bool dir = 0) {
  for (int i = 0, u, v; i < m; ++i) {
    rd(u, v);
    E[u].push_back(v);
    if (!dir) E[v].push_back(u);
  }
}
template <typename T>
void re(vector<pair<int, T>> E[], int m, bool dir = 0) {
  for (int i = 0, u, v; i < m; ++i) {
    T w;
    rd(u, v, w);
    E[u].push_back({v, w});
    if (!dir) E[v].push_back({u, w});
  }
}
const int N = 12550;
const int M = 1000050;
int n, m, u[M], v[M], w[M], val[N], sum[N], ord[N];
vector<pair<int, int>> E[N];
int main() {
  rd(n, m);
  ra(u, v, m);
  for (int i = 1; i <= m; w[i] = 1, i++)
    E[u[i]].push_back({v[i], i}), E[v[i]].push_back({u[i], i});
  for (int i = 1; i <= n; i++) {
    sum[i] = E[i].size();
    vector<pair<int, int>> cns;
    set<int> bad;
    cns.push_back({i, -1});
    for (pair<int, int> e : E[i])
      if (e.first < i) {
        if (!val[e.first]) {
          val[e.first] = 1;
          w[e.second] = 0;
          sum[i]--;
        }
        cns.push_back(e);
        bad.insert(sum[e.first]);
      }
    while (cns.size()) {
      if (!bad.count(sum[i])) {
        break;
      }
      pair<int, int> o = cns.back();
      cns.pop_back();
      sum[i]++;
      if (o.second == -1)
        val[i] = 1;
      else
        val[o.first] = 0, w[o.second]++;
    }
  }
  vector<int> ans;
  for (int i = 1; i <= n; i++)
    if (val[i]) ans.push_back(i);
  printf("%i\n", ans.size());
  for (int i : ans) printf("%i ", i);
  printf("\n");
  for (int i = 1; i <= m; i++) printf("%i %i %i\n", u[i], v[i], w[i]);
  return 0;
}
