#include <bits/stdc++.h>
using namespace std;
const int maxn = 100086;
int z[maxn], n, m, num, order[maxn][2], last[maxn], ans[maxn], len, in[maxn];
bool flag, ok[maxn];
char s[2];
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= m; i++) {
    scanf("%s", s);
    scanf("%d", &num);
    if (s[0] == '-') {
      if (z[num] == 0) z[num] = -1;
      order[i][0] = -1;
      order[i][1] = num;
    } else {
      if (z[num] == 0) z[num] = 1;
      order[i][0] = 1;
      order[i][1] = num;
    }
  }
  num = 0;
  for (int i = 1; i <= n; i++) {
    if (z[i] == 0)
      ans[++len] = i;
    else {
      if (z[i] == -1) {
        in[i] = 1;
        num++;
      }
      ok[i] = 1;
    }
  }
  for (int i = 1; i <= m; i++) {
    if (order[i][0] == -1) {
      num--;
      in[order[i][1]] = 0;
      if (num) ok[order[i][1]] = 0;
      last[order[i][1]] = i;
      if ((i != m) && (order[i + 1][1] != order[i][1])) ok[order[i][1]] = 0;
    } else {
      in[order[i][1]] = 1;
      if (num) ok[order[i][1]] = 0;
      if (last[order[i][1]] != i - 1) ok[order[i][1]] = 0;
      num++;
      last[order[i][1]] = i;
    }
  }
  for (int i = 1; i <= n; i++)
    if (ok[i]) ans[++len] = i;
  sort(ans + 1, ans + 1 + len);
  printf("%d\n", len);
  if (len) {
    for (int i = 1; i < len; i++) printf("%d ", ans[i]);
    printf("%d", ans[len]);
    printf("\n");
  }
  return 0;
}
