#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;
template <class T, class U>
inline void checkmin(T &x, U y) {
  if (y < x) x = y;
}
template <class T, class U>
inline void checkmax(T &x, U y) {
  if (y > x) x = y;
}
template <class T, class U>
inline bool ifmax(T &x, U y) {
  if (y > x) return x = y, true;
  return false;
}
template <class T, class U>
inline bool ifmin(T &x, U y) {
  if (y < x) return x = y, true;
  return false;
}
template <class T>
inline void sort(T &a) {
  sort(a.begin(), a.end());
}
template <class T>
inline void rsort(T &a) {
  sort(a.rbegin(), a.rend());
}
template <class T>
inline void reverse(T &a) {
  reverse(a.begin(), a.end());
}
template <class T, class U>
inline istream &operator>>(istream &str, pair<T, U> &p) {
  return str >> p.first >> p.second;
}
template <class T>
inline istream &operator>>(istream &str, vector<T> &a) {
  for (auto &i : a) str >> i;
  return str;
}
bool check(int now, int start) { return (start + 1) / 2 <= now; }
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(12);
  srand(94385);
  int n, m;
  cin >> n >> m;
  vector<pair<int, int>> G(m);
  vector<int> cnt(n);
  for (auto &edge : G) {
    int u, v;
    cin >> u >> v;
    --u, --v;
    ++cnt[u], ++cnt[v];
    edge = {u, v};
  }
  vector<int> start = cnt;
  while (signed(G.size()) > (n + m + 1) / 2) {
    int ptr = signed(G.size()) - 1;
    for (int i = signed(G.size()) - 1; i >= 0; --i) {
      if (check(cnt[G[i].first] - 1, start[G[i].first]) &&
          check(cnt[G[i].second] - 1, start[G[i].second])) {
        --cnt[G[i].first];
        --cnt[G[i].second];
        swap(G[i], G[ptr--]);
      }
    }
    G.resize(ptr + 1);
  }
  cout << signed(G.size()) << '\n';
  for (auto i : G) cout << i.first + 1 << ' ' << i.second + 1 << '\n';
  return 0;
}
