#include <bits/stdc++.h>
using namespace std;
const int maxn = 2000 * 100 + 5;
const int mod = 1000000007;
int n, m, p[maxn], mark[3 * maxn];
vector<int> ans, odd;
vector<pair<int, int> > adj[maxn];
void tour(int v) {
  while (p[v] < adj[v].size()) {
    int id = adj[v][p[v]].second, u = adj[v][p[v]].first;
    if (mark[id] == 0) {
      mark[id] = 1;
      tour(u);
    }
    p[v]++;
  }
  ans.push_back(v);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n >> m;
  for (int i = 1; i <= m; i++) {
    int u, v;
    cin >> u >> v;
    adj[v].push_back({u, i});
    adj[u].push_back({v, i});
  }
  for (int i = 1; i <= n; i++) {
    if ((int)adj[i].size() % 2 == 1) odd.push_back(i);
  }
  for (int i = 0; i < odd.size(); i += 2) {
    m++;
    adj[odd[i]].push_back({odd[i + 1], m});
    adj[odd[i + 1]].push_back({odd[i], m});
  }
  if (m % 2 == 1) {
    m++;
    adj[n].push_back({n, m});
  }
  cout << m << endl;
  tour(1);
  reverse(ans.begin(), ans.end());
  for (int i = 0; i < ans.size(); i++) {
    if (i % 2 == 1) {
      cout << ans[i] << " " << ans[i - 1] << endl;
      cout << ans[i] << " " << ans[i + 1] << endl;
    }
  }
}
