#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000007;
int rd[1000001];
bool srt(pair<int, int> &a, pair<int, int> &b) {
  return rd[a.first] > rd[b.first];
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n, m;
  cin >> n >> m;
  vector<vector<pair<int, int>>> g(n + 1);
  for (int i = 0; i <= n; i++) rd[i] = 0;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    int tx = min(x, y);
    int ty = max(x, y);
    ++rd[tx];
    ++rd[ty];
    g[tx].push_back(make_pair(ty, 0));
  }
  for (int i = 1; i <= n; i++) {
    rd[i] = rd[i] / 2;
  }
  for (int i = 1; i <= n; i++) {
    sort(g[i].begin(), g[i].end(), srt);
    for (int j = 0; j < g[i].size(); j++) {
      int cv = g[i][j].first;
      if (rd[i] && rd[cv]) {
        g[i][j].second = 1;
        --rd[i];
        --rd[cv];
        --m;
      }
    }
  }
  cout << m << endl;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < g[i].size(); j++) {
      if (g[i][j].second == 0) {
        cout << i << " " << g[i][j].first << endl;
      }
    }
  }
  return 0;
}
