#include <bits/stdc++.h>
using namespace std;
template <typename T>
T sqr(T x) {
  return x * x;
}
const int inf = 1e9 + 7;
const long long llinf = (long long)1e18;
const unsigned long long ullinf = (unsigned long long)1e19;
const int maxn = 110000;
const long double eps = 1e-7;
int a[110000], s[110000], f[110000];
bool b[110000];
int main() {
  int n, m;
  scanf("%d %d\n", &n, &m);
  int s = 0, q = 0;
  bool shift2 = false;
  for (int i = 1; i <= m; i++) {
    char c;
    int x;
    scanf("%c %d\n", &c, &x);
    x--;
    if (s) q++;
    if (c == '+') {
      f[x] = i;
      b[x] = true;
      s++;
    } else {
      a[x] += i - f[x];
      if (!b[x]) q = i;
      if (b[x]) s--;
      b[x] = false;
    }
  }
  for (int i = 0; i < n; i++) {
    if (b[i]) {
      shift2 = true;
      a[i] += m + 1 - f[i];
    }
  }
  q += shift2;
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] == q || !a[i]) ans++;
  }
  printf("%d\n", ans);
  for (int i = 0; i < n; i++)
    if (a[i] == q || !a[i]) {
      printf(--ans ? "%d " : "%d\n", i + 1);
    }
}
