#include <bits/stdc++.h>
using namespace std;
const int N = 121111;
char c[N];
int id[N];
bool vis[N];
bool t[N];
int s[N];
int last[N];
int main() {
  ios::sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  memset(s, 0, sizeof(s));
  for (int i = 0; i < m; i++) cin >> c[i] >> id[i];
  memset(vis, true, sizeof(vis));
  memset(t, 0, sizeof(t));
  int l = 0;
  for (int i = 0; i < m; i++)
    if (c[i] == '-' && (!t[id[i]])) {
      t[id[i]] = true;
      l++;
    } else if (c[i] == '+')
      t[id[i]] = true;
  for (int i = 0; i < m; i++)
    if (c[i] == '+') {
      l++;
      if (l == 1 && (i == 0 || id[i - 1] == id[i])) {
      } else
        vis[id[i]] = false;
    } else {
      l--;
      if (l == 0 && (i == m - 1 || id[i + 1] == id[i])) {
      } else
        vis[id[i]] = false;
    }
  int ans = 0;
  for (int i = 1; i <= n; i++)
    if (vis[i]) ans++;
  if (ans) {
    cout << ans << '\n';
    for (int i = 1; i <= n; i++)
      if (vis[i]) cout << i << ' ';
    cout << '\n';
  } else
    cout << "0\n";
  return 0;
}
