#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 14;
char t[maxn];
int n, m, a[maxn];
int main() {
  ios::sync_with_stdio(0), cin.tie(0);
  int cur = 0;
  cin >> n >> m;
  set<int> s;
  for (int i = 0; i < m; i++) {
    cin >> t[i] >> a[i];
    if (t[i] == '-') {
      cur += s.count(a[i]) == 0;
      s.erase(a[i]);
    } else
      s.insert(a[i]);
  }
  set<int> goods;
  for (int i = 1; i <= n; i++) goods.insert(i);
  for (int i = 0; i < m; i++)
    if (t[i] == '-') {
      cur--;
      if (cur > 0 || i < m - 1 && (t[i + 1] == '-' || a[i + 1] != a[i]))
        goods.erase(a[i]);
    } else {
      if (cur > 0 || i > 0 && (t[i - 1] == '+' || a[i - 1] != a[i]))
        goods.erase(a[i]);
      cur++;
    }
  cout << goods.size() << '\n';
  for (auto x : goods) cout << x << ' ';
  cout << '\n';
}
