#include <bits/stdc++.h>
using namespace std;
const int inf = 1000000000;
const int MOD = 1000000007;
const double pi = acos(-1.0);
char mode[100009];
int who[100009];
int f[100009];
bool used[100009];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = (1); i <= (m); ++i) {
    cin >> mode[i] >> who[i];
    who[i]--;
    if (!used[who[i]]) f[who[i]] = mode[i];
    used[who[i]] = true;
  }
  bitset<100009> cur, ans, tl;
  for (int i = (0); i <= (n - 1); ++i) ans[i] = true;
  tl.reset();
  vector<int> na;
  for (int i = (0); i <= (n - 1); ++i)
    if (f[i] == '-')
      cur[i] = true;
    else if (!f[i])
      na.push_back(i);
  for (int i = (1); i <= (m); ++i) {
    if (cur != tl) ans &= cur;
    if (mode[i] == '+') {
      cur[who[i]] = 1;
    } else {
      cur[who[i]] = 0;
    }
    if (cur == tl) continue;
    ans &= cur;
  }
  for (int i = (0); i <= ((int)((na).size()) - 1); ++i) ans[na[i]] = 1;
  int cnt = 0;
  for (int i = (0); i <= (n - 1); ++i) cnt += ans[i];
  cout << cnt << endl;
  for (int i = (0); i <= (n - 1); ++i)
    if (ans[i]) cout << i + 1 << " ";
  cout << endl;
}
