#include <bits/stdc++.h>
using namespace std;
const int maxn = 100005;
multiset<int> G[maxn];
vector<int> odd;
vector<int> ans;
int degree[maxn];
void dfs(int u) {
  while (!G[u].empty()) {
    int v = *G[u].begin();
    G[u].erase(G[u].begin());
    G[v].erase(G[v].find(u));
    dfs(v);
  }
  ans.push_back(u);
}
int main() {
  int sum_node, sum_edges;
  cin >> sum_node >> sum_edges;
  for (int i = 0; i < sum_edges; i++) {
    int u, v;
    cin >> u >> v;
    G[u].insert(v);
    G[v].insert(u);
    degree[u]++;
    degree[v]++;
  }
  for (int i = 1; i <= sum_node; i++) {
    if (degree[i] & 1) odd.push_back(i);
  }
  for (int i = 0; i < odd.size(); i += 2) {
    G[odd[i]].insert(odd[i + 1]);
    G[odd[i + 1]].insert(odd[i]);
    sum_edges++;
  }
  if (sum_edges & 1) {
    G[1].insert(1);
    G[1].insert(1);
    sum_edges++;
  }
  cout << sum_edges << endl;
  dfs(1);
  for (int i = 0; i < ans.size() - 1; i++) {
    if (i & 1)
      printf("%d %d\n", ans[i], ans[i + 1]);
    else
      printf("%d %d\n", ans[i + 1], ans[i]);
  }
  return 0;
}
