#include <bits/stdc++.h>
using namespace std;
multiset<int> edge[100001];
int inv(0);
void addedge(int x, int y) {
  edge[x].insert(y);
  edge[y].insert(x);
}
void trace(int x) {
  while (!edge[x].empty()) {
    multiset<int>::iterator it = edge[x].begin();
    int y = *it;
    edge[x].erase(it);
    edge[y].erase(edge[y].find(x));
    trace(y);
    if (inv) {
      printf("%d %d\n", y, x);
    } else {
      printf("%d %d\n", x, y);
    }
    inv ^= 1;
  }
}
int main() {
  int n, m, i, j, x, y;
  scanf("%d%d", &n, &m);
  for (i = 0; i < m; i++) {
    scanf("%d%d", &x, &y);
    addedge(x, y);
  }
  for (i = 1; i < n + 1; i++) {
    if (edge[i].size() % 2) {
      j = i;
      for (i++; i < n + 1; i++) {
        if (edge[i].size() % 2) {
          addedge(i, j);
          m++;
          break;
        }
      }
    }
  }
  printf("%d\n", m + (m & 1));
  trace(1);
  if (m % 2) {
    printf("1 1\n");
  }
}
