#include <bits/stdc++.h>
using namespace std;
int n, m;
char rec1[110000], str[5];
int a[110000], b[110000], c[110000], lab[110000], d[110000], last[110000];
bool p[110000], pd[110000];
int main() {
  scanf("%d%d", &n, &m);
  memset(p, 1, sizeof p);
  int sum = 0;
  for (int i = 1; i <= m; i++) {
    scanf("%s", str);
    rec1[i] = str[0];
    scanf("%d", &lab[i]);
    if (rec1[i] == '+')
      d[lab[i]] = 1;
    else
      d[lab[i]]--;
    if (d[lab[i]] < 0) pd[lab[i]] = 1;
    p[lab[i]] = 0;
  }
  for (int i = 1; i <= n; i++)
    if (pd[i]) sum++;
  int tim = sum > 0;
  for (int i = 1; i <= m; i++) {
    if (rec1[i] == '+')
      sum++;
    else
      sum--;
    tim += sum > 0;
  }
  for (int i = 1; i <= m; i++) {
    if (rec1[i] == '+')
      last[lab[i]] = i;
    else
      b[lab[i]] += i - last[lab[i]];
  }
  for (int i = 1; i <= n; i++)
    if (d[i] > 0) b[i] += m + 1 - last[i];
  for (int i = 1; i <= n; i++) p[i] = p[i] | (b[i] == tim);
  int ans = 0;
  for (int i = 1; i <= n; i++) ans += p[i];
  cout << ans << endl;
  if (!ans) return 0;
  for (int i = 1; i <= n; i++)
    if (p[i]) {
      ans--;
      if (!ans)
        printf("%d\n", i);
      else
        printf("%d ", i);
    }
  return 0;
}
