#include <bits/stdc++.h>
using namespace std;
const int MAX = 100005;
char c[MAX];
int a[MAX];
bool seen[MAX], ans[MAX];
int main() {
  ios::sync_with_stdio(false);
  memset(ans, true, sizeof(ans));
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    cin >> c[i] >> a[i];
    a[i]--;
  }
  int cnt = 0;
  for (int i = 0; i < m; i++) {
    if (c[i] == '-' && !seen[a[i]]) cnt++;
    seen[a[i]] = true;
  }
  for (int i = 0; i < m; i++)
    if (c[i] == '+') {
      if ((i > 0 && a[i - 1] != a[i]) || cnt) ans[a[i]] = false;
      cnt++;
    } else {
      cnt--;
      if ((i < m - 1 && a[i + 1] != a[i]) || cnt) ans[a[i]] = false;
    }
  int size = 0;
  for (int i = 0; i < n; i++)
    if (ans[i]) size++;
  cout << size << endl;
  for (int i = 0; i < n; i++)
    if (ans[i]) cout << i + 1 << " ";
  cout << endl;
  return 0;
}
