#include <bits/stdc++.h>
using namespace std;
int st[100002], dd[100002], ms[100002][2];
int main() {
  int i, j, n, m, count, dcount = 0, ps, flag;
  char ch;
  cin >> n >> m;
  for (i = 0; i < m; i++) {
    cin >> ch;
    if (ch == '+')
      ms[i][0] = 1;
    else
      ms[i][0] = -1;
    cin >> ms[i][1];
  }
  count = 0;
  for (i = 0; i < m; i++) {
    if (ms[i][0] == 1 && dd[ms[i][1]] == 0) {
      dd[ms[i][1]] = 1;
      st[ms[i][1]] = -1;
    } else if (ms[i][0] == 1)
      dd[ms[i][1]] = 1;
    else if (dd[ms[i][1]] == 0) {
      count++;
      st[ms[i][1]] = 1;
      dd[ms[i][1]] = -1;
      ps = ms[i][1];
    } else
      dd[ms[i][1]] = -1;
  }
  for (i = 0; i <= n; i++) {
    if (st[i] == 0)
      dd[i] = 0;
    else
      dd[i] = 1;
  }
  if (count == 0) ps = ms[0][1];
  flag = 0;
  for (i = 0; i < m; i++) {
    if (ms[i][0] == 1)
      count++;
    else if (ms[i][0] == -1 && ms[i][1] != ps)
      count--;
    else {
      if (count > 1) {
        flag = 1;
        break;
      } else if (!(i == (m - 1) || ms[i + 1][1] == ps)) {
        flag = 1;
        break;
      } else if (ms[i + 1][1] == ps)
        i++;
    }
  }
  if (flag == 0) {
    dd[ps] = 0;
  }
  for (i = 1; i <= n; i++) {
    if (dd[i] == 0) dcount++;
  }
  cout << dcount << endl;
  for (i = 1; i <= n; i++) {
    if (dd[i] == 0) cout << i << " ";
  }
  return 0;
}
