#include <bits/stdc++.h>
using namespace std;
bool init[300005];
vector<pair<int, int> > edges[100005];
int n, m;
vector<int> ret;
void dfs(int curr) {
  while ((int)(edges[curr]).size()) {
    pair<int, int> out = edges[curr].back();
    edges[curr].pop_back();
    if (!init[out.second]) {
      init[out.second] = true;
      dfs(out.first);
      ret.push_back(curr);
    }
  }
}
void solve() {
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    edges[a].push_back({b, i});
    edges[b].push_back({a, i});
  }
  vector<int> odd;
  for (int i = 1; i <= n; i++) {
    if ((int)(edges[i]).size() % 2) odd.push_back(i);
  }
  assert((int)(odd).size() % 2 == 0);
  for (int i = 0; i < (int)(odd).size(); i += 2) {
    edges[odd[i]].push_back({odd[i + 1], m});
    edges[odd[i + 1]].push_back({odd[i], m});
    m++;
  }
  if (m % 2) {
    edges[1].push_back(pair<int, int>(1, m));
    m++;
  }
  cerr << m << endl;
  for (int i = 1; i <= n; i++) {
    dfs(i);
  }
  cout << m << "\n";
  for (int i = 0; i < (int)(ret).size(); i++) {
    if (i % 2)
      cout << ret[i] << " " << ret[(i + 1) % (int)(ret).size()] << "\n";
    else
      cout << ret[(i + 1) % (int)(ret).size()] << " " << ret[i] << "\n";
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
}
