#include <bits/stdc++.h>
using namespace std;
const int mx = 1e5 + 10;
char op[mx];
int idx[mx];
int main() {
  char s[3];
  int n, m, v;
  scanf("%d %d", &n, &m);
  set<int> ans;
  for (int i = 1; i <= n; i++) ans.insert(i);
  set<int> inside;
  set<int> inicial;
  for (int i = 0; i < m; i++) {
    scanf("%s %d", s, &v);
    op[i] = s[0];
    idx[i] = v;
    ans.erase(v);
    if (op[i] == '+') {
      inside.insert(v);
    } else {
      if (inside.count(v) == 0) inicial.insert(v);
      inside.erase(v);
    }
  }
  set<int>::iterator it;
  if (inicial.size() == 0) {
    int leader = -1;
    bool ok = true;
    for (int i = 0; i < m; i++) {
      if (op[i] == '+') {
        if (inicial.size() == 0) {
          if (leader == -1 || leader == idx[i]) {
            leader = idx[i];
          } else
            ok = false;
        }
        inicial.insert(idx[i]);
      } else {
        inicial.erase(idx[i]);
        if (inicial.size() == 0) {
          if (leader == -1 || leader == idx[i]) {
            leader = idx[i];
          } else {
            ok = false;
          }
        } else {
          if (idx[i] == leader) {
            ok = false;
          }
        }
      }
    }
    if (ok && leader != -1) {
      ans.insert(leader);
    }
  } else {
    set<int> possibles;
    for (it = inicial.begin(); it != inicial.end(); it++) possibles.insert(*it);
    set<int> leader;
    for (int i = 0; i < m; i++) {
      if (op[i] == '+') {
        if (inicial.size() == 0)
          leader.insert(idx[i]);
        else
          possibles.erase(idx[i]);
        inicial.insert(idx[i]);
      } else {
        inicial.erase(idx[i]);
        if (inicial.size() == 0)
          leader.insert(idx[i]);
        else
          possibles.erase(idx[i]);
      }
    }
    if (leader.size() == 1) {
      it = leader.begin();
      if (possibles.count(*it) == 1) ans.insert(*it);
    } else if (leader.size() == 0) {
      for (it = possibles.begin(); it != possibles.end(); it++) {
        ans.insert(*it);
      }
    } else {
    }
  }
  printf("%d\n", ans.size());
  int cnt = 0;
  for (it = ans.begin(); it != ans.end(); it++, cnt++) {
    if (cnt != 0) printf(" ");
    printf("%d", *it);
  }
  return 0;
}
