#include <bits/stdc++.h>
using namespace std;
const int MX = 1e5 + 1;
int n, m;
multiset<int> adj[MX];
vector<int> seq;
void dfs(int u) {
  while (!adj[u].empty()) {
    int v = *adj[u].begin();
    adj[u].erase(adj[u].begin());
    adj[v].erase(adj[v].find(u));
    dfs(v);
    seq.push_back(v);
  }
}
int main() {
  scanf("%d%d", &n, &m);
  int x, y;
  for (int i = 0; i < m; i++) {
    scanf("%d%d", &x, &y);
    adj[x].insert(y);
    adj[y].insert(x);
  }
  vector<int> odd;
  for (int i = 1; i <= n; i++) {
    int sz = adj[i].size();
    if (sz % 2) {
      odd.push_back(i);
    }
  }
  for (int i = 0; i < odd.size(); i++) {
    if (i % 2) {
      adj[odd[i - 1]].insert(odd[i]);
      adj[odd[i]].insert(odd[i - 1]);
      m++;
    }
  }
  if (m % 2) {
    adj[1].insert(1);
    adj[1].insert(1);
  }
  dfs(1);
  seq.push_back(1);
  printf("%d\n", seq.size() - 1);
  for (int i = 1; i < seq.size(); i++) {
    if (i % 2)
      printf("%d %d\n", seq[i], seq[i - 1]);
    else
      printf("%d %d\n", seq[i - 1], seq[i]);
  }
  return 0;
}
