#include <bits/stdc++.h>
using namespace std;
const double Pi = acos(-1);
vector<set<int>> g;
vector<int> deg;
int n, m, ans, rem;
void Remove() {
  if (rem == 0) return;
  vector<int> deg2 = deg;
  for (int u = 0; u < n; u++) {
    priority_queue<pair<int, int>> pq;
    for (int v : g[u]) pq.push(pair<int, int>(deg2[v], v));
    while (!pq.empty() && deg2[u] > deg[u] / 2 + (deg[u] % 2 != 0)) {
      int degv = pq.top().first;
      int v = pq.top().second;
      pq.pop();
      if (degv <= deg[v] / 2 + (deg[v] % 2 != 0)) continue;
      deg2[u]--;
      deg2[v]--;
      g[u].erase(g[u].find(v));
      g[v].erase(g[v].find(u));
      rem--;
      if (rem == 0) return;
    }
  }
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout.tie(0);
  cin >> n >> m;
  deg.resize(n);
  g.resize(n);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    g[u].insert(v);
    g[v].insert(u);
    deg[u]++;
    deg[v]++;
  }
  ans = min(m, (n + m) / 2 + ((n + m) % 2 != 0));
  rem = m - ans;
  Remove();
  cout << ans << '\n';
  set<pair<int, int>> Edge;
  for (int u = 0; u < n; u++)
    for (int v : g[u]) Edge.insert(pair<int, int>(min(u, v), max(u, v)));
  for (pair<int, int> uv : Edge)
    cout << uv.first + 1 << ' ' << uv.second + 1 << '\n';
  return 0;
}
