3
1 1 5
1 3 42
1 2 42
 2
42 23
1 2 10
 10
45792697 27183921 4791060 77070594 27286110 66957065 19283638 2944837 26775511 65379701
5 8 25
8 10 94
1 4 14
9 7 96
4 2 16
2 6 58
2 3 99
6 8 21
8 9 87
 5
3 1 2 6 5
1 2 3
2 3 1
4 3 9
5 3 1
 10
26 31 21 57 56 44 54 58 79 97
2 1 277
1 8 91
1 7 380
4 1 649
10 5 799
10 1 940
8 6 627
6 3 177
9 6 685
 10
8 100 62 38 26 51 26 23 77 32
6 8 29
4 1 82
7 8 66
7 10 67
8 9 98
6 1 14
1 5 48
3 1 58
2 9 90
 2
23 42
1 2 10
 1
42
 3
1 5 1
1 3 42
1 2 42
 10
1 1 1 1 1 1 1 1 1 1
1 2 5
1 3 5
1 4 5
1 5 5
1 6 5
1 7 5
1 8 5
1 9 5
1 10 5
 3
1 1 1
1 2 42
2 3 42
 3
5 1 1
1 3 42
1 2 24

3 1042.0638260857 1 727.3238618387 6 283959805416.40496826
 3 192.0000000000 1 13952642.4776933547 8 544327.1927847408 2 727.3238618387 1 0.0000000000 2 1042.0638260857 1 100.6230589875 2 544.3822186663 1 389.7666169867
#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void read(T &x) {
  int f = 0;
  x = 0;
  char ch = getchar();
  for (; !isdigit(ch); ch = getchar()) f |= (ch == '-');
  for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
  if (f) x = -x;
}
const int N = 500005;
struct edge {
  int v, l;
} e[N];
int h[N], d[N], vis[N], cnt, n, m, a, b, ty, ans;
void add(int a, int b) {
  e[cnt] = (edge){b, h[a]}, h[a] = cnt++;
  e[cnt] = (edge){a, h[b]}, h[b] = cnt++;
}
void dfs(int u) {
  while (h[u] >= 0) {
    int k = h[u];
    h[u] = e[k].l;
    if (vis[k]) continue;
    vis[k ^ 1] = 1;
    dfs(e[k].v);
    if (ty)
      printf("%d %d\n", u, e[k].v);
    else
      printf("%d %d\n", e[k].v, u);
    ty ^= 1;
  }
}
int main() {
  read(n), read(m);
  fill(h + 1, h + n + 1, -1);
  for (int i = (1); i <= (m); i++) {
    read(a), read(b);
    d[a]++, d[b]++;
    add(a, b), ans++;
  }
  int las = 0;
  for (int i = (1); i <= (n); i++)
    if (d[i] & 1) {
      if (las)
        add(las, i), las = 0, ans++;
      else
        las = i;
    }
  if (ans & 1) add(1, 1), ans++;
  printf("%d\n", ans);
  dfs(1);
  return 0;
}
