#include <iostream>
#include <vector>
#include <map>

using namespace std;

const int MAXN = 20000;

map< pair< int, int>, pair<int, int> > kek;
vector< pair<int, int> > g[MAXN], order[MAXN];
vector<bool> used[MAXN];
int deg[MAXN];
vector<int> bad;
int ind;

void dfs(int v) {
    for (int i = 0; i < g[v].size(); i++) {
        int to = g[v][i].first;
        if (!used[v][i]) {
            used[v][i] = true;
            used[to][kek[make_pair(v, i)].second] = true;
            //cout << v + 1 << " " << i << ", " << to + 1 << " " << kek[make_pair(v, i)].second << endl;
            dfs(to);
            if (g[v][i].second) {
                ind++;
            } else
                order[ind].emplace_back(to, v);
        }
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, x, y;
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> x >> y;
        x--, y--;
        g[x].emplace_back(y, 0);
        g[y].emplace_back(x, 0);
        kek[make_pair(x, g[x].size() - 1)] = make_pair(y, g[y].size() - 1);
        kek[make_pair(y, g[y].size() - 1)] = make_pair(x, g[x].size() - 1);
        used[x].push_back(false);
        used[y].push_back(false);
        deg[x]++;
        deg[y]++;
    }
    for (int i = 0; i < n; i++) {
        if (deg[i] & 1) bad.push_back(i);
    }
    for (int i = 0; i < bad.size(); i += 2) {
        g[bad[i]].emplace_back(bad[i + 1], 1);
        g[bad[i + 1]].emplace_back(bad[i], 1);
        kek[make_pair(bad[i], g[bad[i]].size() - 1)] = make_pair(bad[i + 1], g[bad[i + 1]].size() - 1);
        kek[make_pair(bad[i + 1], g[bad[i + 1]].size() - 1)] = make_pair(bad[i], g[bad[i]].size() - 1);
        used[bad[i]].push_back(false);
        used[bad[i + 1]].push_back(false);
    }
    dfs(0);
    /*for (int i = 0; i < ind + 1; i++) {
        for (auto &j : order[i])
            cout << j.first + 1 << " " << j.second + 1;
        cout << endl;
    }*/
    //cout << endl;
    cout << ind << endl;
    for (int i = 1; i < ind + 1; i++) {
        for (auto &j : order[i])
            cout << j.first + 1 << " ";
        if (i != ind or order[0].empty())
            cout << order[i][order[i].size() - 1].second + 1 << endl;
    }
    if (!order[0].empty()) {
        for (auto &j : order[0])
            cout << j.first + 1 << " ";
        cout << order[0][order[0].size() - 1].second + 1;
    }
    return 0;
}