#include <bits/stdc++.h>
using namespace std;
char str[2];
int n, m, a[101000], b[101000], ans, l[101000], v[101000], s[101000];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; i++) {
    scanf("%s%d", str, &b[i]);
    a[i] = (str[0] == '+' ? 1 : -1);
  }
  for (int i = 1; i <= m; i++) {
    if (a[i] < 0 && !l[b[i]]) s[0]++;
    s[i] = a[i];
    l[b[i]] = i;
  }
  for (int i = 1; i <= m; i++) s[i] += s[i - 1];
  for (int i = 0; i <= m; i++) s[i] = (s[i] > 0);
  for (int i = 1; i <= m; i++) s[i] += s[i - 1];
  memset(l, 0, sizeof l);
  for (int i = 1; i <= m; i++) {
    if (a[i] > 0 &&
        (!l[b[i]] && s[i - 1] > 0 || l[b[i]] && s[i - 1] - s[l[b[i]] - 1] > 0))
      v[b[i]] = 1;
    l[b[i]] = i;
  }
  for (int i = 1; i <= n; i++)
    if (l[i] && a[l[i]] < 0 && s[m] - s[l[i] - 1] > 0) v[i] = 1;
  for (int i = 1; i <= n; i++) ans += !v[i];
  printf("%d\n", ans);
  for (int i = 1; i <= n; i++)
    if (!v[i]) printf("%d ", i);
  return 0;
}
