#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 1;
int n, m;
char ty[maxn];
int id[maxn];
bool ok[maxn];
int state[maxn];
set<int> S;
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= (n); i++) ok[i] = 1;
  int cnt = 0;
  int diff = 0;
  for (int i = 0; i < (m); i++) {
    char op[2];
    scanf("%s%d", op, &id[i]);
    ty[i] = op[0];
    if (!state[id[i]]) {
      if (ty[i] == '+')
        state[id[i]] = 1;
      else {
        state[id[i]] = 2;
        cnt++;
        S.insert(id[i]);
      }
    }
  }
  bool bad = 0;
  int j = 0;
  for (int i = 0; i < (m); i++) {
    if (cnt == 1) {
      int k = *S.begin();
      if (!j)
        j = k;
      else if (j != k)
        j = -1;
      bad = 1;
    }
    if (ty[i] == '+') {
      if (cnt) ok[id[i]] = 0;
      cnt++;
      S.insert(id[i]);
    } else {
      cnt--;
      if (cnt) ok[id[i]] = 0;
      S.erase(id[i]);
    }
  }
  if (cnt == 1) {
    int k = *S.begin();
    if (!j)
      j = k;
    else if (j != k)
      j = -1;
    bad = 1;
  }
  if (bad)
    for (int i = 0; i < (m); i++)
      if (id[i] != j) ok[id[i]] = 0;
  int ans = 0;
  for (int i = 1; i <= (n); i++)
    if (ok[i]) ans++;
  printf("%d\n", ans);
  for (int i = 1; i <= (n); i++)
    if (ok[i]) printf("%d ", i);
}
