#include <bits/stdc++.h>
using namespace std;
const int maxn = 100005;
int n, m, deg[maxn];
vector<int> g[maxn];
vector<int> cycle;
inline void euler(int stnode) {
  stack<int> st;
  st.push(stnode);
  while (!st.empty()) {
    int node = st.top();
    if (g[node].size()) {
      int newnode = g[node].back();
      g[node].pop_back();
      g[newnode].erase(find(g[newnode].begin(), g[newnode].end(), node));
      st.push(newnode);
    } else {
      cycle.push_back(node);
      st.pop();
    }
  }
}
int main() {
  cin >> n >> m;
  for (int i = 1; i <= m; ++i) {
    int x, y;
    cin >> x >> y;
    g[x].push_back(y);
    g[y].push_back(x);
    ++deg[x];
    ++deg[y];
  }
  int last = -1;
  for (int i = 1; i <= n; ++i)
    if (deg[i] % 2 == 1)
      if (last == -1)
        last = i;
      else {
        ++m;
        g[i].push_back(last);
        g[last].push_back(i);
        last = -1;
      }
  if (m & 1) {
    ++m;
    g[1].push_back(1);
    g[1].push_back(1);
  }
  euler(1);
  cout << m << '\n';
  int cnt = 0;
  for (int i = 0; i + 1 < cycle.size(); ++i) {
    if (i % 2 == 0)
      cout << cycle[i] << ' ' << cycle[i + 1] << '\n';
    else
      cout << cycle[i + 1] << ' ' << cycle[i] << '\n';
  }
}
