#include <bits/stdc++.h>
using namespace std;
namespace fastIO {
bool IOerror = 0;
inline char nc() {
  static char buf[100000], *p1 = buf + 100000, *pend = buf + 100000;
  if (p1 == pend) {
    p1 = buf;
    pend = buf + fread(buf, 1, 100000, stdin);
    if (pend == p1) {
      IOerror = 1;
      return -1;
    }
  }
  return *p1++;
}
inline bool blank(char ch) {
  return ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t';
}
inline void read(long long &x) {
  char ch;
  long long f = 1;
  while (blank(ch = nc()))
    ;
  while (ch == '-') f = -f, ch = nc();
  if (IOerror) return;
  for (x = ch - '0'; (ch = nc()) >= '0' && ch <= '9'; x = x * 10 + ch - '0')
    ;
  x *= f;
}
inline void read(int &x) {
  char ch;
  int f = 1;
  while (blank(ch = nc()))
    ;
  while (ch == '-') f = -f, ch = nc();
  if (IOerror) return;
  for (x = ch - '0'; (ch = nc()) >= '0' && ch <= '9'; x = x * 10 + ch - '0')
    ;
  x *= f;
}
inline void read(char *s) {
  char ch;
  while (blank(ch = nc()))
    ;
  if (IOerror) return;
  int i = 0;
  for (; !blank(ch); s[i++] = ch, ch = nc())
    ;
  s[i] = '\0';
}
};  // namespace fastIO
using namespace fastIO;
inline long long read() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
struct edge {
  int to, next, mrk;
} e[400010];
int n, m, cnt = 1;
int head[200010];
int dep[200010];
int ans, ansx[200010], ansy[200010], ansz[200010];
bool mrk[200010];
inline void add(int x, int y, int z) {
  ans++;
  ansx[ans] = x;
  ansy[ans] = y;
  ansz[ans] = z;
}
inline void dfs(int x, int fa, int d, int lnk) {
  vector<int> now;
  mrk[x] = 1;
  dep[x] = d;
  for (int i = head[x]; i; i = e[i].next) {
    if (!mrk[e[i].to]) {
      dfs(e[i].to, x, d + 1, i ^ 1);
      if (!e[i].mrk) now.push_back(i);
    } else if (dep[x] > dep[e[i].to] && fa != e[i].to)
      now.push_back(i);
  }
  if ((now.size() & 1) && fa != -1) now.push_back(lnk);
  int mx = now.size(), xx, yy;
  for (int i = 0; i + 1 < mx; i += 2) {
    xx = e[now[i]].to;
    yy = e[now[i + 1]].to;
    add(xx, x, yy);
    e[now[i]].mrk = e[now[i] ^ 1].mrk = 1;
    e[now[i + 1]].mrk = e[now[i + 1] ^ 1].mrk = 1;
  }
}
inline void ins(int u, int v) {
  e[++cnt].to = v;
  e[cnt].next = head[u];
  head[u] = cnt;
  e[cnt].mrk = 0;
}
inline void insert(int u, int v) {
  ins(v, u);
  ins(u, v);
}
int main() {
  n = read();
  m = read();
  for (int i = 1; i <= m; i++) {
    int x = read(), y = read();
    insert(x, y);
  }
  for (int i = 1; i <= n; i++)
    if (!mrk[i]) dfs(i, -1, 0, -1);
  printf("%d\n", ans);
  for (int i = 1; i <= ans; i++)
    printf("%d %d %d\n", ansx[i], ansy[i], ansz[i]);
}
