#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  vector<pair<int, int> > V(m);
  vector<int> st(n, -1), ans(n, 0);
  for (int i = 0; i < m; i++) {
    char c;
    cin >> c;
    int k;
    cin >> k;
    k--;
    if (c == '+') {
      if (st[k] == -1) st[k] = -2;
      V[i] = make_pair(1, k);
    } else {
      if (st[k] == -1) st[k] = 1;
      V[i] = make_pair(-1, k);
    }
  }
  int cnt = 0;
  set<int> op, cl;
  set<int>::iterator it;
  for (int i = 0; i < n; i++)
    if (st[i] == 1) {
      op.insert(i);
      cnt++;
    } else if (st[i] == -2) {
      cl.insert(i);
    }
  vector<bool> C(n, 0);
  for (int i = 0; i < m; i++) {
    C[V[i].second] = 1;
    if (V[i].first == 1) {
      if (cnt == 0) {
        for (it = cl.begin(); it != cl.end(); it++) {
          if ((*it) != V[i].second) ans[*(it)] = -1;
        }
        cl.clear();
      } else {
        for (it = cl.begin(); it != cl.end(); it++) {
          if ((*it) != V[i].second) ans[*(it)] = -1;
        }
        cl.clear();
        ans[V[i].second] = -1;
      }
      cnt++;
      if (ans[V[i].second] == 0) {
        op.insert(V[i].second);
      }
    } else {
      for (it = cl.begin(); it != cl.end(); it++) {
        if ((*it) != V[i].second) ans[*(it)] = -1;
      }
      cl.clear();
      if (cnt >= 2) {
        ans[V[i].second] = -1;
      }
      op.erase(V[i].second);
      if (ans[V[i].second] == 0) cl.insert(V[i].second);
      cnt--;
    }
  }
  vector<int> Q;
  for (int i = 0; i < n; i++)
    if (ans[i] == 0 || C[i] == 0) Q.push_back(i);
  cout << Q.size() << endl;
  for (int i = 0; i < (int)Q.size(); i++) cout << Q[i] + 1 << " ";
  cout << endl;
  return 0;
}
