#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 100;
multiset<int> G[maxn];
vector<int> odd, ans;
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 n, m;
  int tot_edge = 0;
  scanf("%d%d", &n, &m);
  tot_edge = m;
  while (m--) {
    int u, v;
    scanf("%d%d", &u, &v);
    G[u].insert(v);
    G[v].insert(u);
  }
  for (int i = 1; i <= n; i++) {
    int tot = (int)G[i].size();
    if (tot & 1) odd.push_back(i);
  }
  for (int i = 0; i < (int)odd.size() - 1; i += 2) {
    int u = odd[i];
    int v = odd[i + 1];
    G[u].insert(v);
    G[v].insert(u);
    ++tot_edge;
  }
  if (tot_edge & 1) G[1].insert(1), G[1].insert(1), tot_edge++;
  dfs(1);
  printf("%d\n", tot_edge);
  for (int i = 0; i < (int)ans.size() - 1; i++) {
    if (i & 1)
      cout << ans[i] << ' ' << ans[i + 1] << '\n';
    else
      cout << ans[i + 1] << ' ' << ans[i] << ' ' << '\n';
  }
  return 0;
}
