#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
bool f[maxn], x[maxn];
int a[maxn];
char c[maxn];
bool p = 0;
int ans = 0, d = 0, n, m;
set<int> on;
int main() {
  memset(f, 0, sizeof f);
  cin >> n >> m;
  for (int i = 1; i <= m; i++) {
    cin >> c[i] >> a[i];
    if (c[i] == '+')
      x[a[i]] = 1;
    else if (!x[a[i]]) {
      on.insert(a[i]);
      x[a[i]] = 1;
    }
  }
  d = on.size();
  if (d) p = 1;
  for (int i = 1; i <= m; i++) {
    if (c[i] == '+') {
      d++;
      if (p) f[a[i]] = 1;
      p = 1;
      on.insert(a[i]);
    }
    if (c[i] == '-') {
      d--;
      on.erase(a[i]);
      if (d)
        f[a[i]] = 1;
      else if (i < m && (a[i] != a[i + 1] || c[i + 1] == '-'))
        f[a[i]] = 1;
      else if (i < m) {
        d++;
        on.insert(a[i]);
        i++;
      }
    }
  }
  for (int i = 1; i <= n; i++)
    if (f[i] == 0) ans++;
  cout << ans << endl;
  for (int i = 1; i <= n; i++)
    if (f[i] == 0) cout << i << " ";
  cout << endl;
  return 0;
}
