#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 10;
const int MOD = 1e9 + 7;
const int MAXN = 1e6 + 10;
const int LOG = 20;
const long long BINF = 1e18 + 10;
const long long LINF = LLONG_MAX;
const long double EPS = 1e-9;
const long double PI = acos(-1);
inline void error() {
  cout << -1;
  exit(0);
}
int tin[MAXN], tout[MAXN], timer;
bool used[MAXN];
vector<vector<int> > g, ans;
map<pair<int, int>, int> first;
bool ancestor(int a, int b) {
  if (!tin[b]) {
    return false;
  }
  return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}
void dfs(int v, int p) {
  used[v] = true;
  timer++;
  tin[v] = timer;
  vector<int> arr;
  for (auto u : g[v]) {
    if (!used[u]) {
      dfs(u, v);
    }
  }
  timer++;
  tout[v] = timer;
  for (auto u : g[v]) {
    if (ancestor(v, u) && !first[make_pair(min(v, u), max(v, u))]) {
      arr.push_back(u);
      first[make_pair(min(v, u), max(v, u))] = 1;
    }
  }
  if (int(arr.size()) & 1) {
    if (p != -1) {
      first[make_pair(min(p, v), max(p, v))] = true;
      arr.push_back(p);
    }
  }
  for (int i = 0; i + 1 < arr.size(); i += 2) {
    ans.push_back(vector<int>{arr[i], v, arr[i + 1]});
  }
}
int n, m, a, b;
inline void source() {
  cin >> n >> m;
  g.resize(n + 1);
  for (register int i(1); i <= m; i++) {
    cin >> a >> b;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  for (register int i(1); i <= n; i++) {
    if (!used[i]) {
      dfs(i, -1);
    }
  }
  cout << ans.size() << "\n";
  for (register int i(0); i < ans.size(); i++) {
    copy(ans[i].begin(), ans[i].end(), ostream_iterator<int>(cout, " "));
    cout << "\n";
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  srand(time(0));
  source();
  return 0;
}
