#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
int const N = 3e5 + 20;
int n, m, x[N], y[N], din[N], dout[N];
vector<int> g[N];
bool vis[N];
int dfs(int v) {
  int ret = (din[v] & 1);
  vis[v] = 1;
  for (int i : g[v]) {
    int u = x[i] ^ y[i] ^ v;
    if (vis[u]) continue;
    if (dfs(u)) {
      dout[x[i]]--, din[x[i]]++;
      dout[y[i]]++, din[y[i]]--;
      swap(x[i], y[i]);
      ret ^= 1;
    }
  }
  return ret;
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    cin >> x[i] >> y[i];
    x[i]--, y[i]--;
    dout[x[i]]++, din[y[i]]++;
    g[x[i]].push_back(i);
    g[y[i]].push_back(i);
  }
  for (int i = 0, j = -1; i < n; i++) {
    if ((din[i] + dout[i]) & 1) {
      if (j == -1)
        j = i;
      else
        x[m] = i, y[m] = j, dout[i]++, din[j]++, m++, j = -1;
    }
  }
  if (m & 1) x[m] = y[m] = 0, dout[0]++, din[0]++, m++;
  dfs(0);
  cout << m << '\n';
  for (int i = 0; i < m; i++) cout << x[i] + 1 << ' ' << y[i] + 1 << '\n';
}
