#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool upmin(T &x, T y) {
  return y < x ? x = y, 1 : 0;
}
template <typename T>
inline bool upmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
const long double eps = 1e-9;
const long double pi = acos(-1);
const int oo = 1 << 30;
const long long loo = 1ll << 62;
const int mods = 998244353;
const int MAXN = 400005;
const int INF = 0x3f3f3f3f;
namespace FastIO {
constexpr int SIZE = (1 << 21) + 1;
int num = 0, f;
char ibuf[SIZE], obuf[SIZE], que[65], *iS, *iT, *oS = obuf,
                                                *oT = obuf + SIZE - 1, c;
inline void flush() {
  fwrite(obuf, 1, oS - obuf, stdout);
  oS = obuf;
}
inline void putc(char c) {
  *oS++ = c;
  if (oS == oT) flush();
}
inline void getc(char &c) {
  for (c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++);
       (c < 'a' || c > 'z') && c != EOF;
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    ;
}
template <class I>
inline void read(I &x) {
  for (f = 1, c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                              (iS == iT ? EOF : *iS++))
                            : *iS++);
       c < '0' || c > '9';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    if (c == '-') f = -1;
  for (x = 0; c >= '0' && c <= '9';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    x = (x << 3) + (x << 1) + (c & 15);
  x *= f;
}
template <class I>
inline void print(I x) {
  if (x < 0) putc('-'), x = -x;
  if (!x) putc('0');
  while (x) que[++num] = x % 10 + 48, x /= 10;
  while (num) putc(que[num--]);
}
struct Flusher_ {
  ~Flusher_() { flush(); }
} io_Flusher_;
}  // namespace FastIO
using FastIO ::print;
using FastIO ::putc;
using FastIO ::read;
vector<int> V, Ans;
int edgenum = 1, lst, num = 0, d[MAXN], head[MAXN], flag[MAXN << 1];
struct enode {
  int to, nxt;
} e[MAXN << 1];
void add(int u, int v) {
  e[++edgenum] = (enode){v, head[u]}, head[u] = edgenum;
}
void dfs(int x) {
  for (int &i = head[x]; i; i = e[i].nxt) {
    if (flag[i]) continue;
    flag[i] = flag[i ^ 1] = 1;
    int v = e[i].to;
    dfs(v);
  }
  Ans.push_back(x);
}
signed main() {
  int n, m;
  read(n), read(m);
  for (int i = 1; i <= m; ++i) {
    int u, v;
    read(u), read(v);
    add(u, v), add(v, u);
    ++d[u], ++d[v];
  }
  for (int i = 1; i <= n; ++i)
    if (d[i] & 1) V.push_back(i);
  for (int i = 1; i + i <= (int)V.size(); ++i)
    add(V[i + i - 2], V[i + i - 1]), add(V[i + i - 1], V[i + i - 2]);
  if (((edgenum ^ 1) >> 1) & 1) add(1, 1), add(1, 1);
  printf("%d\n", ((edgenum ^ 1) >> 1));
  dfs(1);
  for (int i = 0; i < (int)Ans.size() - 1; ++i)
    if (i & 1)
      print(Ans[i]), putc(' '), print(Ans[i + 1]), putc('\n');
    else
      print(Ans[i + 1]), putc(' '), print(Ans[i]), putc('\n');
  return 0;
}
