#include <bits/stdc++.h>
using namespace std;
char cmd[100010];
int a[100010];
set<int> on;
set<int> off;
int n, m;
int used[100010];
int main() {
  while (cin >> n >> m) {
    on.clear();
    off.clear();
    memset(used, 0, sizeof(used));
    for (int i = 1; i <= m; ++i) {
      cin >> cmd[i] >> a[i];
    }
    for (int i = 1; i <= m; ++i) {
      if (cmd[i] == '-') {
        if (!used[a[i]]) {
          on.insert(a[i]);
        }
      }
      used[a[i]] = 1;
    }
    memset(used, 0, sizeof(used));
    for (int i = 1; i <= m; ++i) {
      if (cmd[i] == '+') {
        on.insert(a[i]);
        if (on.size() > 1)
          used[a[i]] = 1;
        else
          off.insert(a[i]);
      } else {
        on.erase(a[i]);
        if (on.size() > 0)
          used[a[i]] = 1;
        else
          off.insert(a[i]);
      }
    }
    if (off.size() > 1) {
      for (set<int>::iterator i = off.begin(); i != off.end(); ++i) {
        used[*i] = 1;
      }
    }
    int sum = 0;
    for (int i = 1; i <= n; ++i) {
      if (!used[i]) sum++;
    }
    if (sum == 0) {
      printf("0\n");
      continue;
    }
    printf("%d\n", sum);
    for (int i = 1; i <= n; ++i) {
      if (!used[i]) printf("%d ", i);
    }
    printf("\n");
  }
}
