#include <bits/stdc++.h>
#pragma G++ optimize(2)
using namespace std;
inline long long read() {
  char ch = ' ', last;
  long long ans = 0;
  while (ch < '0' || ch > '9') last = ch, ch = getchar();
  while (ch >= '0' && ch <= '9') ans = ans * 10 + int(ch - '0'), ch = getchar();
  if (last == '-') return -ans;
  return ans;
}
void write(long long x) {
  if (x >= 10) write(x / 10);
  putchar(x % 10 + '0');
}
int n, m, in[2000005], f[2000005];
bool book[2000005];
struct ED {
  long long from, to;
} edge[2000005];
void init() {
  n = read(), m = read();
  for (int i = 1; i <= m; i++) {
    edge[i] = ED{read(), read()};
    in[edge[i].from]++, in[edge[i].to]++, f[edge[i].from]++, f[edge[i].to]++;
  }
}
int main() {
  init();
  srand(20040708);
  while (1) {
    random_shuffle(edge + 1, edge + m + 1);
    memcpy(f, in, sizeof(in));
    memset(book, false, sizeof(book));
    int cnt = m - ((n + m + 1) / 2), cnt2 = m;
    for (int i = 1; i <= m; i++) {
      if (cnt <= 0) break;
      if (f[edge[i].from] - 1 >= (in[edge[i].from] + 1) / 2)
        if (f[edge[i].to] - 1 >= (in[edge[i].to] + 1) / 2)
          book[i] = true, cnt--, f[edge[i].to]--, f[edge[i].from]--, cnt2--;
    }
    if (cnt <= 0) {
      cout << cnt2 << endl;
      for (int i = 1; i <= m; i++)
        if (!book[i]) cout << edge[i].from << ' ' << edge[i].to << endl;
      break;
    }
  }
  return 0;
}
