#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
const int maxn = 1e6 + 5;
int ecnt;
set<int> G[maxn];
int in[maxn];
bool vis[maxn];
deque<pair<int, int> > path;
void dfs(int u) {
  vis[u] = 1;
  if (G[u].size() == 0) return;
  while (G[u].size()) {
    auto it = *G[u].begin();
    G[u].erase(G[u].begin());
    G[it].erase(u);
    path.push_back({u, it});
    dfs(it);
  }
}
int n, m;
vector<pair<int, int> > path2;
vector<pair<int, int> > res;
void cal() {
  int len = path2.size();
  if (len % 2 == 0) {
    for (int j = 0; j < len; j++)
      if (j == len - 1 || j % 2 == 0) res.push_back(path2[j]);
  } else {
    for (int j = 0; j < len; j++)
      if (j % 2 == 0) res.push_back(path2[j]);
  }
  path2.clear();
}
void work() {
  42;
  for (auto it : path) {
    42;
  }
  bool have = false;
  for (auto it : path) {
    if (it.first == n + 1 || it.second == n + 1) {
      have = true;
      break;
    }
  }
  if (have) {
    while (path.front().first != n + 1 && path.front().second != n + 1) {
      auto it = path.front();
      path.pop_front();
      path.push_back(it);
    }
  }
  while (!path.empty()) {
    auto it = path.front();
    if (path.front().first == n + 1 || path.front().second == n + 1) {
      cal();
    } else {
      path2.push_back(it);
    }
    path.pop_front();
  }
  cal();
}
int in2[maxn];
int main() {
  scanf("%d %d", &n, &m);
  int u, v;
  for (int i = 1; i <= m; i++) {
    scanf("%d %d", &u, &v);
    G[u].insert(v);
    G[v].insert(u);
    in[u]++;
    in[v]++;
  }
  for (int i = 1; i <= n; i++) {
    if (in[i] % 2) {
      G[i].insert(n + 1);
      G[n + 1].insert(i);
    }
  }
  for (int i = 1; i <= n; i++) {
    if (vis[i]) continue;
    dfs(i);
    work();
  }
  cout << res.size() << endl;
  for (auto it : res) {
    printf("%d %d\n", it.first, it.second);
  }
  return 0;
}
