#include <bits/stdc++.h>
using namespace std;
using LL = long long;
constexpr int N = 1e5 + 5;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, m;
  cin >> n >> m;
  vector<pair<char, int>> log(m);
  for (int i = 0; i < m; i++) {
    cin >> log[i].first >> log[i].second;
  }
  set<int> inMeeting, candidate;
  vector<bool> isLeader(n + 1, true);
  for (int i = 0; i < m; i++) {
    int p = log[i].second;
    if (log[i].first == '+') {
      if (!inMeeting.empty()) {
        isLeader[p] = false;
      }
      if (i > 0) {
        if (log[i - 1].second != p) {
          isLeader[p] = false;
        }
      }
      inMeeting.insert(p);
    } else {
      if (inMeeting.count(p)) {
        inMeeting.erase(p);
      } else {
        for (auto x : candidate) {
          isLeader[x] = false;
        }
        candidate.clear();
      }
      if (!inMeeting.empty()) {
        isLeader[p] = false;
      }
      if (i + 1 < m) {
        if (log[i + 1].second != p) {
          isLeader[p] = false;
        }
      }
    }
    if (isLeader[p]) candidate.insert(p);
  }
  vector<int> ans;
  for (int i = 1; i <= n; i++)
    if (isLeader[i]) ans.push_back(i);
  cout << ans.size() << "\n";
  for (int x : ans) cout << x << ' ';
}
