#include <bits/stdc++.h>
using namespace std;
int n, m;
struct M {
  char x;
  int id;
  void init() { scanf("%s%d", &x, &id); }
} a[100010];
set<int> que;
bool no[100010], vis[100010];
int ans[100010];
int main() {
  while (~scanf("%d%d", &n, &m)) {
    memset(no, 0, sizeof(no));
    memset(vis, 0, sizeof(vis));
    for (int i = 1; i <= m; i++) {
      a[i].init();
      if (a[i].x == '+' && vis[a[i].id] == 0)
        vis[a[i].id] = 1;
      else if (a[i].x == '-' && vis[a[i].id] == 0)
        que.insert(a[i].id);
    }
    int mb = -1;
    for (int i = 1; i <= m; i++) {
      if (a[i].x == '-') {
        if (que.size() > 1)
          no[a[i].id] = 1;
        else if (que.size() == 1)
          mb = a[i].id;
        que.erase(a[i].id);
      } else if (a[i].x == '+') {
        if (que.size() != 0)
          no[a[i].id] = 1;
        else if (mb != -1 && a[i].id != mb) {
          no[mb] = 1, no[a[i].id] = 1;
        }
        que.insert(a[i].id);
      }
    }
    int len = 0;
    for (int i = 1; i <= n; i++) {
      if (no[i] == 0) ans[len++] = i;
    }
    printf("%d\n", len);
    if (len != 0) {
      for (int i = 0; i < len - 1; i++) printf("%d ", ans[i]);
      printf("%d", ans[len - 1]);
    }
  }
  return 0;
}
