#include <bits/stdc++.h>
using namespace std;
vector<int> v, o, O;
int a[100500], b[100005], f[100005], l[100005], w[100005], ANS[100005], n, m, k;
char c;
int main() {
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    getchar();
    scanf("%c %d", &c, &b[i]);
    a[i] = (c == '+');
  }
  for (int i = 0; i < m; i++) {
    if (!w[b[i]] && !a[i]) l[b[i]] = 1, k++;
    w[b[i]] = 1;
  }
  for (int i = 0; i < m; i++) {
    if (l[b[i]]) {
      if (k != 1) ANS[b[i]] = 1;
      l[b[i]] = 0;
      k--;
      if (k == 0) o.push_back(b[i]);
    } else {
      if (k > 0) ANS[b[i]] = 1;
      l[b[i]] = 1;
      k++;
      if (k == 1) o.push_back(b[i]);
    }
  }
  sort(o.begin(), o.end());
  for (int i = 0; i < o.size(); i++) {
    if (!i || o[i] != o[i - 1]) O.push_back(o[i]);
  }
  if (O.size() > 1)
    for (int i = 0; i < O.size(); i++) ANS[O[i]] = 1;
  for (int i = 1; i <= n; i++)
    if (!ANS[i]) v.push_back(i);
  cout << v.size() << endl;
  for (int i = 0; i < v.size(); i++) printf("%d ", v[i]);
  cout << endl;
}
