#include <bits/stdc++.h>
using namespace std;
template <class C>
void mini(C& a4, C b4) {
  a4 = min(a4, b4);
}
template <class C>
void maxi(C& a4, C b4) {
  a4 = max(a4, b4);
}
template <class T1, class T2>
ostream& operator<<(ostream& out, pair<T1, T2> pair) {
  return out << "(" << pair.first << ", " << pair.second << ")";
}
template <class A, class B, class C>
struct Triple {
  A first;
  B second;
  C third;
};
template <class T>
void ResizeVec(T&, vector<long long>) {}
template <class T>
void ResizeVec(vector<T>& vec, vector<long long> sz) {
  vec.resize(sz[0]);
  sz.erase(sz.begin());
  if (sz.empty()) {
    return;
  }
  for (T& v : vec) {
    ResizeVec(v, sz);
  }
}
struct Edge {
  long long a, inv, used;
};
const long long N = 1e5 + 5;
vector<Edge> slo[N];
void AddEdge(long long a, long long b) {
  ;
  long long inv1 = ((long long)(slo[b]).size());
  long long inv2 = ((long long)(slo[a]).size());
  if (a == b) {
    inv1++;
  }
  slo[a].push_back(Edge{b, inv1, 0});
  slo[b].push_back(Edge{a, inv2, 0});
}
vector<long long> ans;
long long deg[N];
long long beg[N];
void Euler(long long v) {
  ;
  for (long long& ii = beg[v]; ii < ((long long)(slo[v]).size());) {
    Edge& e = slo[v][ii];
    long long nei = e.a;
    ii++;
    if (e.used) {
      continue;
    }
    assert(slo[nei][e.inv].used == 0);
    slo[nei][e.inv].used = 1;
    Euler(nei);
    ans.push_back(nei);
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  long long n, m;
  cin >> n >> m;
  ;
  for (long long i = (1); i <= (m); ++i) {
    long long a, b;
    cin >> a >> b;
    ;
    deg[a]++;
    deg[b]++;
    AddEdge(a, b);
  }
  long long ____prev = 0;
  for (long long i = (1); i <= (n); ++i) {
    if (deg[i] % 2 == 1) {
      if (____prev) {
        AddEdge(i, ____prev);
        ____prev = 0;
        m++;
      } else {
        ____prev = i;
      }
    }
  }
  if (m % 2 == 1) {
    AddEdge(1, 1);
  }
  Euler(1);
  for (long long i = (1); i <= (n); ++i) {
    for (long long j = 0; j < (((long long)(slo[i]).size())); ++j) {
      if (0) cout << slo[i][j].used << " ";
    }
    if (0) cout << "\n";
  }
  cout << ((long long)(ans).size()) << "\n";
  ans.push_back(ans[0]);
  for (long long i = 0; i < ((long long)(ans).size()) - 1; i++) {
    if (i % 2) {
      cout << ans[i] << " " << ans[i + 1] << "\n";
    } else {
      cout << ans[i + 1] << " " << ans[i] << "\n";
    }
  }
  return 0;
}
