#include <bits/stdc++.h>
using namespace std;
int n, m, i, j, a[100001], zf, b[100001], ans[100001], ans1;
char s[100001][2];
int main() {
  scanf("%d%d", &n, &m);
  for (i = 1; i <= m; i++) scanf("%s %d", s[i], &b[i]);
  for (i = 1; i <= m; i++) {
    if (!a[b[i]] && s[i][0] == '-') zf++;
    a[b[i]]++;
  }
  if (m > 1) {
    for (i = 1; i <= m - 1; i++) {
      if (s[i][0] == '+') {
        if ((b[i - 1] != 0 && b[i - 1] != b[i]) || zf) ans[b[i]] = 1;
        zf++;
      } else {
        if (b[i + 1] != b[i]) ans[b[i]] = 1;
        zf--;
      }
    }
    if (s[m][0] == '+') {
      if (zf || b[m - 1] != b[m]) ans[b[m]] = 1;
    } else {
      if (zf > 1) ans[b[m]] = 1;
    }
  }
  for (i = 1; i <= n; i++)
    if (!ans[i]) ans1++;
  printf("%d\n", ans1);
  for (i = 1; i <= n; i++)
    if (!ans[i]) printf("%d ", i);
}
