#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
char c[N];
int id[N], ng[N];
int init[N];
int main() {
  cin.sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = (0); i < (int)(m); ++i) cin >> c[i] >> id[i];
  memset(init, -1, sizeof(init));
  for (int i = (0); i < (int)(m); ++i) {
    if (init[--id[i]] < 0) {
      init[id[i]] = c[i] == '-';
    }
  }
  int cnt = count(init, init + n, 1);
  if (cnt)
    for (int i = (0); i < (int)(m); ++i)
      if (init[i] == 0) ng[i] = 1;
  set<int> cand;
  for (int i = (0); i < (int)(m); ++i) {
    if (c[i] == '+') {
      if (cnt != 0)
        ng[id[i]] = 1;
      else
        cand.insert(id[i]);
      ++cnt;
    } else {
      --cnt;
      if (cnt != 0)
        ng[id[i]] = 1;
      else
        cand.insert(id[i]);
    }
  }
  if (cand.size() > 1)
    for (auto i : cand) ng[i] = 1;
  int ans = count(ng, ng + n, 0);
  cout << ans << endl;
  if (ans) {
    bool f = false;
    for (int i = (0); i < (int)(n); ++i) {
      if (ng[i]) continue;
      if (f) cout << ' ';
      f = true;
      cout << i + 1;
    }
    cout << endl;
  }
  return 0;
}
