#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  set<int> chat, notLeader, uncertain;
  set<int>::iterator ite;
  cin >> n >> m;
  getchar();
  char pre_c;
  int pre_d;
  for (int i = 0; i < m; i++) {
    char c;
    int d;
    c = getchar();
    cin >> d;
    getchar();
    if (c == '+') {
      if (i > 0 && pre_c == '-' && pre_d != d) {
        notLeader.insert(d);
        notLeader.insert(pre_d);
      } else if (!chat.empty())
        notLeader.insert(d);
      else {
        uncertain.insert(d);
      }
      chat.insert(d);
    } else {
      if (!chat.count(d)) {
        notLeader.insert(uncertain.begin(), uncertain.end());
        uncertain.clear();
      } else {
        chat.erase(d);
      }
      if (!chat.empty())
        notLeader.insert(d);
      else {
        uncertain.insert(d);
      }
    }
    pre_c = c;
    pre_d = d;
  }
  cout << n - notLeader.size() << endl;
  for (int i = 1; i <= n; i++) {
    if (!notLeader.count(i)) cout << i << " ";
  }
  return 0;
}
