#include <bits/stdc++.h>
using namespace std;
const long long N = 3e5;
map<pair<long long, long long>, long long> mapp;
long long visit[N];
vector<long long> g[N];
long long hi[N];
vector<pair<long long, pair<long long, long long> > > ans;
void dfs(long long v, long long p, long long h) {
  vector<long long> be;
  vector<long long> son;
  vector<long long> sons;
  hi[v] = h;
  visit[v] = 1;
  for (long long i = 0; i < g[v].size(); i++) {
    long long u = g[v][i];
    if (v == 3) {
    }
    if (visit[u] == 0) {
      dfs(u, v, h + 1);
      sons.push_back(u);
    } else {
      if (u != p && visit[u] == 1) {
        if (mapp[{v, u}] == 1) {
          mapp[{v, u}] = 0;
          mapp[{u, v}] = 0;
          be.push_back(u);
        }
      }
    }
  }
  if (v == 3) {
  }
  for (long long i = 0; i < sons.size(); i++) {
    long long u = sons[i];
    if (mapp[{u, v}] == 1) {
      son.push_back(u);
    }
  }
  if (v == 3) {
  }
  long long s = son.size();
  for (long long i = 0; i < s - 1; i += 2) {
    ans.push_back({son[i], {v, son[i + 1]}});
    mapp[{son[i], v}] = 0;
    mapp[{v, son[i]}] = 0;
    mapp[{son[i + 1], v}] = 0;
    mapp[{v, son[i + 1]}] = 0;
  }
  if (v == 4) {
  }
  long long b = be.size();
  if (v == 3) {
  }
  for (long long i = b - 1; i > 0; i -= 2) {
    ans.push_back({be[i], {v, be[i - 1]}});
  }
  if (v == 4) {
  }
  if (v == 3) {
  }
  if (son.size() % 2 == 1) {
    if (be.size() % 2 == 1) {
      ans.push_back({son[son.size() - 1], {v, be[0]}});
      mapp[{son[son.size() - 1], v}] = 0;
      mapp[{v, son[son.size() - 1]}] = 0;
    } else {
      ans.push_back({son[son.size() - 1], {v, p}});
      mapp[{son[son.size() - 1], v}] = 0;
      mapp[{v, son[son.size() - 1]}] = 0;
      mapp[{p, v}] = 0;
      mapp[{v, p}] = 0;
    }
  } else {
    if (v == 4) {
    }
    if (be.size() % 2 == 1) {
      ans.push_back({p, {v, be[0]}});
      mapp[{p, v}] = 0;
      mapp[{v, p}] = 0;
    }
  }
  return;
}
int32_t main() {
  long long n, m;
  cin >> n >> m;
  for (long long i = 0; i < m; i++) {
    long long u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
    mapp[{u, v}] = 1;
    mapp[{v, u}] = 1;
  }
  for (long long i = 1; i <= n; i++) {
    if (visit[i] == 0) {
      dfs(i, -1, 0);
    }
  }
  long long t = 0;
  for (long long i = 0; i < ans.size(); i++) {
    if (ans[i].first != -1 && ans[i].second.first != -1 &&
        ans[i].second.second != -1)
      t++;
  }
  cout << t << endl;
  for (long long i = 0; i < ans.size(); i++) {
    if (ans[i].first != -1 && ans[i].second.first != -1 &&
        ans[i].second.second != -1)
      cout << ans[i].first << " " << ans[i].second.first << " "
           << ans[i].second.second << endl;
  }
}
