#include <bits/stdc++.h>
using namespace std;
vector<pair<char, int> > vec;
bool used[100100];
bool p[100100];
int n, m;
set<int> st, us;
int main() {
  scanf("%d %d", &n, &m);
  memset(used, false, sizeof(used));
  for (int i = 0; i < m; i++) {
    pair<char, int> a;
    cin >> a.first >> a.second;
    a.second--;
    vec.push_back(a);
  }
  for (int i = 0; i < m; i++) {
    if (!used[vec[i].second]) {
      if (vec[i].first == '-')
        st.insert(vec[i].second);
      else
        us.insert(vec[i].second);
      used[vec[i].second] = true;
    }
  }
  set<int>::iterator it;
  if (st.size() > 0) {
    memset(p, false, sizeof(p));
    for (int i = 0; i < n; i++)
      if (!used[i]) p[i] = true;
    for (it = st.begin(); it != st.end(); it++) p[*it] = true;
  } else
    memset(p, true, sizeof(p));
  for (int i = 0; i < m; i++) {
    char c = vec[i].first;
    int id = vec[i].second;
    if (c == '-') {
      st.erase(id);
      if (st.size() > 0) p[id] = false;
      if (p[id]) us.insert(id);
    } else {
      set<int>::iterator it = us.find(id);
      if (it != us.end()) us.erase(it);
      for (it = us.begin(); it != us.end(); it++) p[*it] = false;
      st.insert(id);
      us.clear();
    }
  }
  int ans = 0;
  for (int i = 0; i < n; i++)
    if (p[i]) ans++;
  printf("%d\n", ans);
  if (ans == 0) return 0;
  int cnt = 0;
  for (int i = 0; i < n; i++)
    if (p[i]) {
      cnt++;
      if (cnt == ans)
        printf("%d\n", i + 1);
      else
        printf("%d ", i + 1);
    }
  return 0;
}
