#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  vector<bool> check(n + 1, true);
  set<int> S, off;
  int l[m][2];
  for (int i = 1; i <= n; i++) off.insert(i);
  for (int i = 0; i < m; i++) {
    char c;
    cin >> c >> l[i][1];
    if (c == '+') {
      l[i][0] = 1;
      if (check[l[i][1]]) check[l[i][1]] = false;
    } else {
      l[i][0] = 0;
      if (check[l[i][1]]) {
        S.insert(l[i][1]);
        off.erase(l[i][1]);
      }
    }
  }
  vector<bool> isl(n + 1, true);
  for (int i = 1; i <= n; i++)
    if (check[i]) off.erase(i);
  for (int i = 0; i < m; i++) {
    if (S.empty() == 0) {
      for (set<int>::iterator it = off.begin(); it != off.end(); it++)
        isl[*it] = check[*it] = false;
      off.clear();
    }
    if (l[i][0] == 0) {
      S.erase(l[i][1]);
      off.insert(l[i][1]);
      if (S.empty() == 0) {
        for (set<int>::iterator it = off.begin(); it != off.end(); it++)
          isl[*it] = check[*it] = false;
        off.clear();
        isl[l[i][1]] = false;
      }
    } else {
      S.insert(l[i][1]);
      off.erase(l[i][1]);
    }
  }
  if (S.empty() == 0) {
    for (set<int>::iterator it = off.begin(); it != off.end(); it++)
      isl[*it] = check[*it] = false;
    off.clear();
  }
  vector<int> ans;
  for (int i = 1; i <= n; i++)
    if (isl[i]) ans.push_back(i);
  cout << ans.size() << '\n';
  for (unsigned i = 0; i < ans.size(); i++) printf("%d ", ans[i]);
}
