#include <bits/stdc++.h>
using namespace std;
int N, M;
bool notboss[100010];
int type[100010], id[100010];
int first[100010];
set<int> In, Out;
set<int> Elim;
int main() {
  cin >> N >> M;
  for (int i = 1; i <= M; i++) {
    char op;
    cin >> op >> id[i];
    if (op == '-')
      type[i] = -1;
    else
      type[i] = 1;
  }
  for (int i = 1; i <= M; i++)
    if (first[id[i]] == 0) first[id[i]] = type[i];
  for (int i = 1; i <= N; i++)
    if (first[i] == -1)
      In.insert(i);
    else if (first[i] == 1)
      Out.insert(i);
  if (In.size() != 0) {
    for (set<int>::iterator it = Out.begin(); it != Out.end(); ++it)
      notboss[*it] = 1;
    Out.clear();
  }
  for (int i = 1; i <= M; i++)
    if (type[i] == 1) {
      Out.erase(id[i]);
      In.insert(id[i]);
      for (set<int>::iterator it = Out.begin(); it != Out.end(); ++it)
        notboss[*it] = 1;
      Out.clear();
    } else {
      In.erase(id[i]);
      if (In.size() != 0) notboss[id[i]] = 1;
      if (notboss[id[i]] == 0) Out.insert(id[i]);
    }
  int ans = 0;
  for (int i = 1; i <= N; i++)
    if (notboss[i] == 0) ans++;
  cout << ans << '\n';
  for (int i = 1; i <= N; i++)
    if (notboss[i] == 0) cout << i << ' ';
  cout << '\n';
  return 0;
}
