#include <bits/stdc++.h>
using namespace std;
int n, m, ans[100005], front[100005], g[100005], x[100005], p[100005];
int app[100005];
int main() {
  scanf("%d %d", &n, &m);
  memset(app, -1, sizeof(app));
  for (int i = 1; i <= m; i++) {
    char c = getchar();
    int opt;
    scanf("%c%*c%d", &c, &opt);
    if (c == '-')
      p[i] = 0, x[i] = opt;
    else
      p[i] = 1, x[i] = opt;
    if (app[x[i]] == -1) {
      app[x[i]] = 1 - p[i];
    }
  }
  int now = 0;
  for (int i = 1; i <= n; i++)
    if (app[i] == 1) now++;
  for (int i = 1; i <= n; i++) ans[i] = 1;
  front[0] = 0;
  for (int i = 1; i <= m; i++)
    if (!p[i])
      front[i] = x[i];
    else
      front[i] = front[i - 1];
  g[m + 1] = n + 1;
  for (int i = m; i; i--)
    if (p[i])
      g[i] = x[i];
    else
      g[i] = g[i + 1];
  for (int i = 1; i <= m; i++)
    if (p[i]) {
      if (now > 0) ans[x[i]] = 0;
      if (front[i] && front[i] != x[i]) ans[x[i]] = 0;
      now++;
    } else {
      now--;
      if (g[i] != n + 1 && g[i] != x[i]) ans[x[i]] = 0;
      if (now > 0) ans[x[i]] = 0;
    }
  int tans = 0;
  for (int i = 1; i <= n; i++)
    if (ans[i]) tans++;
  printf("%d\n", tans);
  for (int i = 1; i <= n; i++)
    if (ans[i]) printf("%d ", i);
  return 0;
}
