#include <bits/stdc++.h>
using namespace std;
const long double pi = 3.1415926535897932384626433832795l;
template <typename T>
inline auto sqr(T x) -> decltype(x * x) {
  return x * x;
}
template <typename T>
inline T abs(T x) {
  return x > T() ? x : -x;
}
template <typename T1, typename T2>
inline bool umx(T1& a, T2 b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T1, typename T2>
inline bool umn(T1& a, T2 b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
const int N = 100100, M = 500100;
struct Input {
  int n, m;
  vector<pair<int, int> > a[N];
  bool read() {
    if (scanf("%d %d", &n, &m) != 2) return 0;
    for (int i = 0; i < int(m); ++i) {
      int u, v;
      scanf("%d %d", &u, &v);
      u--, v--;
      a[u].push_back(make_pair(v, i));
      a[v].push_back(make_pair(u, i));
    }
    return 1;
  }
  void init(const Input& input) { *this = input; }
};
struct Data : Input {
  vector<pair<int, int> > e;
  void write() {
    cout << int(e.size()) << endl;
    for (int i = 0; i < int(e.size()); ++i) {
      printf("%d %d\n", e[i].first + 1, e[i].second + 1);
    }
  }
  virtual void solve() {}
  virtual void clear() { *this = Data(); }
};
struct Solution : Data {
  bool use[M];
  vector<int> ord;
  void dfs(int v) {
    for (int i = 0; i < int(a[v].size()); ++i) {
      int to = a[v][i].first, idx = a[v][i].second;
      if (use[idx]) {
        swap(a[v][i], a[v][(int)a[v].size() - 1]);
        a[v].pop_back();
        i--;
        continue;
      }
      use[idx] = 1;
      dfs(to);
    }
    ord.push_back(v);
  }
  void solve() {
    int lst = -1;
    int kol = 0;
    for (int i = 0; i < int(n); ++i) {
      if ((int)a[i].size() & 1) {
        if (lst < 0) {
          lst = i;
        } else {
          a[i].push_back(make_pair(lst, m + kol));
          a[lst].push_back(make_pair(i, m + kol++));
          lst = -1;
        }
      }
    }
    if ((m + kol) & 1) {
      a[0].push_back(make_pair(0, m + kol));
    }
    dfs(0);
    for (int i = 0; i < int(ord.size() - 1); ++i) {
      if (i & 1) {
        e.push_back(make_pair(ord[i + 1], ord[i]));
      } else {
        e.push_back(make_pair(ord[i], ord[i + 1]));
      }
    }
  }
  void clear() { *this = Solution(); }
};
Solution sol;
int main() {
  cout.setf(ios::showpoint | ios::fixed);
  cout.precision(20);
  sol.read();
  sol.solve();
  sol.write();
  return 0;
}
