#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void chkmin(T &a, T b) {
  if (a > b) a = b;
}
template <class T>
inline void chkmax(T &a, T b) {
  if (a < b) a = b;
}
int sum[110000], out[110000], last[110000];
int cnt, ans[110000], pre[110000];
int op[110000], id[110000], vst[110000];
int main() {
  int tot, cur, i, u, N, M;
  char ch;
  scanf("%d%d", &N, &M);
  memset(last, -1, sizeof(last));
  tot = 0;
  cur = 0;
  for (i = 0; i < M; i++) {
    scanf(" %c %d", &ch, &u);
    u--;
    if (ch == '+')
      op[i] = 1;
    else
      op[i] = 0;
    id[i] = u;
    pre[u] = 1;
    if (!vst[u] && op[i] == 0) cur++;
    vst[u] = 1;
  }
  if (cur) tot++;
  for (i = 0; i < M; i++) {
    u = id[i];
    if (op[i]) {
      cur++;
      last[u] = i;
      out[u] = 0;
    } else {
      cur--;
      sum[u] += i - last[u];
      out[u] = 1;
    }
    if (cur) tot++;
  }
  int k = 0;
  for (i = 0; i < N; i++)
    if (!out[i]) sum[i] += M - last[i], k = 1;
  cnt = 0;
  for (i = 0; i < N; i++) {
    if (!vst[i] || sum[i] == tot) ans[cnt++] = i;
  }
  printf("%d\n", cnt);
  for (i = 0; i < cnt; i++)
    printf("%d%c", ans[i] + 1, i == cnt - 1 ? '\n' : ' ');
  return 0;
}
