#include <bits/stdc++.h>
using namespace std;
const int N = 1000 * 100 * 5 + 10;
const long long int mod = 1998244353;
const long long int inf = 1e16;
bool mark[N];
vector<pair<int, int>> adj[N];
vector<int> v;
vector<pair<int, int>> p;
int pt[N];
void travel(int u) {
  while (pt[u] < adj[u].size()) {
    int x = adj[u][pt[u]].first, id = adj[u][pt[u]].second;
    if (!mark[id]) {
      mark[id] = true;
      travel(x);
      p.push_back({u, x});
    }
    pt[u]++;
  }
  return;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    x--;
    y--;
    adj[x].push_back({y, i});
    adj[y].push_back({x, i});
  }
  for (int i = 0; i < n; i++) {
    if (adj[i].size() % 2 == 1) v.push_back(i);
  }
  for (int i = 0; i < v.size(); i += 2) {
    adj[v[i]].push_back({v[i + 1], m});
    adj[v[i + 1]].push_back({v[i], m});
    m++;
  }
  if (m % 2 == 1) {
    adj[0].push_back({0, m});
    m++;
  }
  travel(0);
  cout << m << endl;
  for (int i = 0; i < p.size(); i++) {
    if (i % 2 == 0)
      cout << p[i].first + 1 << ' ' << p[i].second + 1 << endl;
    else
      cout << p[i].second + 1 << ' ' << p[i].first + 1 << endl;
  }
  return 0;
}
