#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
const int inf = 0x7f7f7f7f;
const long long inf_ll = 1ll * inf * inf;
const int Mod = 1e9 + 7;
const double eps = 1e-7;
char c[maxn];
int a[maxn];
int ing[maxn];
bool ans[maxn];
bool book[maxn];
int main() {
  int n, m;
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; ++i) ans[i] = true;
  for (int i = 1; i <= m; ++i) {
    cin >> c[i] >> a[i];
  }
  int cnt = 0;
  for (int i = 1; i <= m; ++i) {
    if (c[i] == '+') book[a[i]] = true;
    if (c[i] == '-' && book[a[i]] == false) ing[++cnt] = a[i];
  }
  for (int i = 1; i <= m; ++i) {
    if (c[i] == '-' && i != m) {
      if (c[i + 1] != '+')
        ans[a[i]] = false;
      else if (a[i + 1] != a[i])
        ans[a[i]] = false;
    }
    if (c[i] == '+' && i != 1) {
      if (c[i - 1] != '-')
        ans[a[i]] = false;
      else if (a[i - 1] != a[i])
        ans[a[i]] = false;
    }
  }
  for (int i = 1; i <= m; ++i) {
    if (c[i] == '+') {
      ing[++cnt] = a[i];
      if (cnt > 1) ans[a[i]] = false;
    }
    if (c[i] == '-') {
      if (cnt > 1) ans[a[i]] = false;
      cnt--;
    }
  }
  int cc = 0;
  for (int i = 1; i <= n; ++i) {
    if (ans[i]) ++cc;
  }
  printf("%d\n", cc);
  for (int i = 1; i <= n; ++i) {
    if (ans[i]) printf("%d ", i);
  }
  return 0;
}
