#include <bits/stdc++.h>
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
using namespace std;
int n, m;
int u, v;
int tot_edge = 0;
int du[610000];
vector<int> odd, ans;
multiset<int> G[610000];
inline void AddEdge(int U, int V) { G[U].insert(V); }
template <class T>
inline void read(T &re) {
  re = 0;
  T sign = 1;
  char tmp;
  while ((tmp = getchar()) && (tmp < '0' || tmp > '9'))
    if (tmp == '-') sign = -1;
  re = tmp - '0';
  while ((tmp = getchar()) && (tmp >= '0' && tmp <= '9'))
    re = re * 10 + (tmp - '0');
  re *= sign;
}
void DFS(int x) {
  while (!G[x].empty()) {
    int v = *G[x].begin();
    G[x].erase(G[x].begin());
    G[v].erase(G[v].find(x));
    DFS(v);
  }
  ans.push_back(x);
}
int main() {
  read(n);
  read(m);
  for (int i = 1; i <= m; i++) {
    read(u);
    read(v);
    AddEdge(u, v);
    AddEdge(v, u);
    tot_edge++;
    du[v]++;
    du[u]++;
  }
  for (int i = 1; i <= n; i++)
    if (du[i] & 1) odd.push_back(i);
  for (int i = 0; i < (int)odd.size(); i += 2) {
    int uu = odd[i], vv = odd[i + 1];
    AddEdge(uu, vv), tot_edge++;
    AddEdge(vv, uu);
  }
  if (tot_edge & 1) {
    tot_edge++, AddEdge(1, 1), AddEdge(1, 1);
  }
  DFS(1);
  printf("%d\n", tot_edge);
  for (int i = 0; i < (int)ans.size() - 1; i++) {
    if (i & 1)
      printf("%d %d\n", ans[i], ans[i + 1]);
    else
      printf("%d %d\n", ans[i + 1], ans[i]);
  }
  return 0;
}
