#include <bits/stdc++.h>
using namespace std;
int rr[100001][2];
bool acc[100001], n2[100001];
set<int> s1;
int tot, n, m;
char s[10];
int main() {
  int last = -1, tt;
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= m; i++) {
    scanf("%s %d", s, &rr[i][1]), rr[i][0] = (s[0] == '-') ? -1 : 1;
    if (!n2[rr[i][1]]) n2[rr[i][1]] = 1, tot++;
    if (!acc[rr[i][1]] && rr[i][0] == -1)
      last = i;
    else
      acc[rr[i][1]] += rr[i][0];
  }
  if (last != -1) rr[0][0] = 1, rr[0][1] = rr[last][1];
  memset(acc, 0, sizeof(acc));
  if (last == -1)
    tt = 1;
  else
    tt = 0;
  int check = 1;
  for (int i = tt; i <= m; i++) {
    if (rr[i][0] == 1)
      s1.insert(rr[i][1]);
    else if (s1.find(rr[i][1]) != s1.end())
      s1.erase(rr[i][1]);
    if (s1.find(rr[tt][1]) == s1.end() && s1.size() != 0) {
      check = 0;
      break;
    }
  }
  if (check) n2[rr[tt][1]] = 0, tot--;
  printf("%d\n", n - tot);
  for (int i = 1; i <= n; i++)
    if (!n2[i]) printf("%d ", i);
  return 0;
}
