#include <bits/stdc++.h>
using namespace std;
int ans = 0;
int i, j, n, m, k, z, y, t, mi, ma;
int a[111111], b[111111], p[111111], x[111111];
char st[11], c[111111];
string s;
int main() {
  cin >> n >> m;
  for (i = 1; i <= m; i++) {
    cin >> c[i] >> x[i];
    if (p[x[i]] == 0 && c[i] == '-') {
      p[x[i]] = 1;
      t++;
      a[x[i]] = 1;
    } else if (p[x[i]] == 0 && c[i] == '+')
      p[x[i]] = -1;
  }
  for (i = 1; i <= m; i++) {
    y = x[i];
    if (t == 0 && z && z != y) {
      b[z] = 1;
      b[y] = 1;
    }
    if (c[i] == '+' && t) b[y] = 1;
    if (z == 0 && t == 0) z = y;
    if (c[i] == '+')
      t++;
    else
      t--;
    if (z == 0 && t == 0) z = y;
    if (c[i] == '-' && t) b[y] = 1;
  }
  for (i = 1; i <= n; i++)
    if (b[i] == 0) ans++;
  printf("%d\n", ans);
  for (i = 1; i <= n; i++)
    if (b[i] == 0) printf("%d ", i);
}
