#include <bits/stdc++.h>
using namespace std;
int a[100000 + 10];
int cont[100000 + 10];
bool flag[100000 + 10];
int main() {
  int n, m;
  char s[2];
  while (~scanf("%d%d", &n, &m)) {
    memset(cont, 0, sizeof(cont));
    memset(flag, true, sizeof(flag));
    int t = 0;
    int x, pre = 0;
    for (int i = 0; i < (m); ++i) {
      scanf("%s", &s);
      scanf("%d", &x);
      if (s[0] == '+')
        a[i] = x, cont[x]++;
      else {
        if (cont[x] == 0) t++;
        cont[x] = 0;
        a[i] = -x;
      }
    }
    for (int i = 0; i < (m); ++i) {
      if (a[i] > 0) {
        if (t > 0 || (i != 0 && a[i - 1] != -a[i])) flag[a[i]] = false;
        ++t;
      } else {
        --t;
        if (!(t == 0 && (i == m - 1 || a[i + 1] == -a[i]))) flag[-a[i]] = false;
      }
    }
    int ans = 0;
    for (int i = (1); i <= (n); ++i)
      if (flag[i] == true) ans++;
    printf("%d\n", ans);
    for (int i = (1); i <= (n); ++i)
      if (flag[i] == true) printf("%d ", i);
    if (ans != 0) printf("\n");
  }
}
