#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int a[maxn];
char ch[maxn][2];
bool vis[maxn];
vector<int> ans;
int main() {
  int n, m, num = 0;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < m; i++) scanf("%s%d", ch[i], &a[i]);
  for (int i = 0; i < m; i++) {
    if (ch[i][0] == '-' && !vis[a[i]]) num++;
    vis[a[i]] = 1;
  }
  memset(vis, 0, sizeof vis);
  for (int i = 0; i < m; i++) {
    if (ch[i][0] == '+') {
      if (num || (i && a[i] != a[i - 1])) vis[a[i]] = 1;
      num++;
    } else {
      num--;
      if (num || (i < m - 1 && a[i] != a[i + 1])) vis[a[i]] = 1;
    }
  }
  for (int i = 1; i <= n; i++)
    if (!vis[i]) ans.push_back(i);
  printf("%d\n", ans.size());
  for (int i = 0; i < ans.size(); i++) {
    if (i == 0)
      printf("%d", ans[i]);
    else
      printf(" %d", ans[i]);
  }
  puts("");
  return 0;
}
