#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
int a[N], v[N], valid[N], lst[N];
char ops[N];
int nr[N];
vector<int> sol;
int main() {
  int n, m, i, x, ins = 0, inss = 0, ok = 0;
  char op;
  scanf("%d %d\n", &n, &m);
  for (i = 1; i <= n; i++) a[i] = 1, lst[i] = 0;
  ins = n;
  for (i = 1; i <= m; i++) scanf("%c %d\n", &ops[i], &nr[i]);
  for (i = 1; i <= m; i++) {
    if (!v[nr[i]]) {
      v[nr[i]] = 1;
      if (ops[i] == '+')
        a[nr[i]] = 0, ins--;
      else if (ops[i] == '-')
        inss++;
    }
  }
  for (i = 1; i <= m; i++) {
    if (inss > 0) ok = 1;
    if (ops[i] == '-') {
      ins--;
      inss--;
      lst[nr[i]] = i;
      if (inss > 0 || (i < m && nr[i + 1] != nr[i])) valid[nr[i]] = 1;
    } else {
      if (inss || lst[nr[i]] != i - 1) valid[nr[i]] = 1;
      ins++;
      inss++;
    }
  }
  for (i = 1; i <= n; i++)
    if (!valid[i]) sol.push_back(i);
  printf("%u\n", sol.size());
  for (i = 0; i < int(sol.size()); i++) printf("%d ", sol[i]);
  printf("\n");
}
