#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:36777216")
using namespace std;
int n, m, a[100005], sum = 0, mx, mx2;
char ch[100005];
bool flag[100005], in[100005];
bool before;
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; i++) flag[i] = true;
  for (int i = 1; i <= m; i++) scanf(" %c%d", &ch[i], &a[i]);
  for (int i = 1; i <= m; i++) {
    if (ch[i] == '-') {
      if (in[a[i]] == false) {
        mx = i;
      } else
        sum--, in[a[i]] = false;
      if (sum != 0) flag[a[i]] = false;
      if (sum == 0) {
        if (a[i + 1] != a[i] && i != m) flag[a[i]] = false;
      }
    } else {
      if (before && a[i - 1] != a[i]) flag[a[i]] = false;
      if (sum != 0) flag[a[i]] = false;
      sum++;
      in[a[i]] = true;
    }
    before = true;
  }
  for (int i = 1; i <= mx; i++) {
    if (ch[i] == '+') flag[a[i]] = false;
  }
  vector<int> vec;
  for (int i = 1; i <= n; i++)
    if (flag[i]) vec.push_back(i);
  cout << vec.size() << endl;
  if (vec.size()) {
    for (int i = 0; i < vec.size(); i++) cout << vec[i] << ' ';
    cout << endl;
  }
}
