#include <bits/stdc++.h>
using namespace std;
template <typename T1, typename T2>
void chkmin(T1 &x, T2 y) {
  if (x > y) x = y;
}
template <typename T1, typename T2>
void chkmax(T1 &x, T2 y) {
  if (x < y) x = y;
}
inline void debug(int x) { fprintf(stderr, "ycx has aked ioi %d times\n", x); }
namespace fastio {
char rbuf[1 << 23], *p1 = rbuf, *p2 = rbuf, wbuf[1 << 23], *p3 = wbuf;
inline char getc() {
  return p1 == p2 &&
                 (p2 = (p1 = rbuf) + fread(rbuf, 1, 1 << 23, stdin), p1 == p2)
             ? -1
             : *p1++;
}
inline void putc(char x) { (*p3++ = x); }
template <typename T>
void read(T &x) {
  x = 0;
  char c = getchar();
  T neg = 0;
  while (!isdigit(c)) neg |= !(c ^ '-'), c = getchar();
  while (isdigit(c)) x = (x << 3) + (x << 1) + (c ^ 48), c = getchar();
  if (neg) x = (~x) + 1;
}
template <typename T>
void recursive_print(T x) {
  if (!x) return;
  recursive_print(x / 10);
  putc(x % 10 ^ 48);
}
template <typename T>
void print(T x) {
  if (!x) putc('0');
  if (x < 0) putc('-'), x = ~x + 1;
  recursive_print(x);
}
template <typename T>
void print(T x, char c) {
  if (!x) putc('0');
  if (x < 0) putc('-'), x = ~x + 1;
  recursive_print(x);
  putc(c);
}
void print_final() { fwrite(wbuf, 1, p3 - wbuf, stdout); }
}  // namespace fastio
const int MAXN = 1.25e4;
const int MAXM = 1e6;
int n, m, u[MAXM + 5], v[MAXM + 5], val[MAXN + 5], w[MAXM + 5], is[MAXN + 5];
vector<pair<int, int> > g[MAXN + 5];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; w[i] = 1, i++) {
    scanf("%d%d", &u[i], &v[i]);
    g[u[i]].push_back(make_pair(v[i], i));
    g[v[i]].push_back(make_pair(u[i], i));
    val[u[i]]++;
    val[v[i]]++;
  }
  for (int i = 1; i <= n; i++) {
    queue<pair<int, int> > q;
    set<int> st;
    for (pair<int, int> p : g[i]) {
      if (p.first > i) continue;
      if (!is[p.first]) w[p.second]--, is[p.first]++, val[i]--;
      q.push(p);
      st.insert(val[p.first]);
    }
    while (st.find(val[i]) != st.end()) {
      pair<int, int> p = q.front();
      q.pop();
      w[p.second]++;
      is[p.first]--;
      val[i]++;
    }
  }
  vector<int> resv;
  for (int i = 1; i <= n; i++)
    if (is[i]) resv.push_back(i);
  printf("%u\n", resv.size());
  for (int i = 0; i < resv.size(); i++)
    printf("%d%c", resv[i], " \n"[i + 1 == resv.size()]);
  for (int i = 1; i <= m; i++) printf("%d %d %d\n", u[i], v[i], w[i]);
  return 0;
}
