#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 5;
const long long linf = 1e18 + 5;
const int N = 1e5 + 5;
int n, m, x[N], ins, outs, only_one;
char ch[N];
bool in[N], out[N], fail[N];
int main() {
  ios ::sync_with_stdio(0);
  cin >> n >> m;
  for (int i = 1; i <= m; i++) {
    cin >> ch[i] >> x[i];
    if (ch[i] == '-' and !in[x[i]]) {
      out[x[i]] = 1;
      ins++;
      only_one = x[i];
    }
    if (ch[i] == '+') in[x[i]] = 1;
  }
  if (!ins) only_one = x[1];
  for (int i = 1; i <= n; i++)
    if (ins and !out[x[i]]) fail[x[i]] = 1;
  for (int i = 1; i <= n; i++) in[i] = out[i];
  for (int i = 1; i <= m; i++) {
    if (ch[i] == '+') {
      fail[x[i]] |= ins - outs > 1 or only_one != x[i];
      ins++;
      in[x[i]] = 1;
      if (only_one != x[i] and !in[only_one]) {
        fail[only_one] = 1;
        only_one = -1;
      }
    }
    if (ch[i] == '-') {
      outs++;
      in[x[i]] = 0;
      if (only_one != x[i]) fail[x[i]] = 1;
      if (only_one == x[i] and ins - outs) fail[x[i]] = 1;
    }
  }
  int ans = 0;
  for (int i = 1; i <= n; i++) ans += !fail[i];
  cout << ans << '\n';
  for (int i = 1; i <= n; i++)
    if (!fail[i]) cout << i << ' ';
  cout << '\n';
  return 0;
}
