#include <bits/stdc++.h>
using namespace std;
const int MAX = 100005;
const int N = 200005;
int from[N], to[N];
stack<pair<int, int> > G[MAX];
stack<int> res;
bool visited[2 * N];
void dfs(int src, int ind = -1) {
  if (ind != -1) {
    visited[ind] = true;
  }
  while (!G[src].empty()) {
    int v = G[src].top().first, e = G[src].top().second;
    G[src].pop();
    if (!visited[e]) {
      dfs(v, e);
    }
  }
  res.push(src);
}
int main() {
  int n, m;
  scanf("%d %d", &n, &m);
  for (int i = 0; i < m; i++) {
    scanf("%d %d", &from[i], &to[i]);
    from[i]--;
    to[i]--;
    G[from[i]].push(make_pair(to[i], i));
    G[to[i]].push(make_pair(from[i], i));
  }
  int pre = -1, cnt = 0;
  for (int i = 0; i < n; i++) {
    if (G[i].size() % 2) {
      if (pre == -1) {
        pre = i;
      } else {
        G[pre].push(make_pair(i, cnt + m));
        G[i].push(make_pair(pre, cnt++ + m));
        pre = -1;
      }
    }
  }
  if ((cnt + m) % 2) {
    G[0].push(make_pair(0, cnt + m));
  }
  dfs(0);
  pre = res.top();
  res.pop();
  printf("%d\n", res.size());
  while (!res.empty()) {
    if (res.size() % 2) {
      printf("%d %d\n", 1 + pre, 1 + res.top());
    } else {
      printf("%d %d\n", 1 + res.top(), 1 + pre);
    }
    pre = res.top();
    res.pop();
  }
  return 0;
}
