#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
const int M = 100005;
int n, m;
int in_degree[N];
bool visited[N];
bool tree_edge[M];
bool directed[M];
vector<int> choose[N];
vector<pair<int, int> > adj[N];
inline void dfs(int u, int p) {
  visited[u] = true;
  for (auto edge : adj[u]) {
    int v = edge.first;
    int i = edge.second;
    if (v == p) {
      continue;
    }
    if (not visited[v]) {
      dfs(v, u);
      tree_edge[i] = true;
    } else if (not directed[i]) {
      in_degree[v]++;
      directed[i] = true;
      choose[v].push_back(u);
    }
  }
}
inline void solve(int u, int p) {
  for (auto edge : adj[u]) {
    int v = edge.first;
    int i = edge.second;
    if ((not tree_edge[i]) || (v == p)) {
      continue;
    }
    solve(v, u);
  }
  if (p != -1) {
    if (in_degree[u] & 1) {
      in_degree[u]++;
      choose[u].push_back(p);
    } else {
      in_degree[p]++;
      choose[p].push_back(u);
    }
  }
}
int main() {
  cin >> n >> m;
  if (m & 1) {
    cout << "No solution" << endl;
    return 0;
  }
  for (int i = 1; i <= m; i++) {
    int u, v;
    cin >> u >> v;
    adj[u].push_back({v, i});
    adj[v].push_back({u, i});
  }
  dfs(1, -1);
  solve(1, -1);
  for (int i = 1; i <= n; i++) {
    while ((int)choose[i].size() > 0) {
      int u = choose[i].back();
      choose[i].pop_back();
      int v = choose[i].back();
      choose[i].pop_back();
      cout << u << ' ' << i << ' ' << v << endl;
    }
  }
}
