#include <bits/stdc++.h>
using namespace std;
template <typename T>
T mabs(const T &a) {
  return a < 0 ? -a : a;
}
const int SZ = 100500;
vector<int> primes;
bool alwaysWas[SZ];
bool nowIn[SZ];
const int llt = SZ - 2;
bool run() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = (0), ei = (n); i < ei; i++) {
    alwaysWas[i] = 1;
  }
  memset(nowIn, 0, sizeof(nowIn));
  int countIn = 0;
  vector<pair<int, int> > moves;
  for (int i = (0), ei = (m); i < ei; i++) {
    char c;
    int num;
    scanf(" %c %d", &c, &num);
    num--;
    if (c == '+') {
      moves.push_back({1, num});
      nowIn[num] = true;
    } else {
      moves.push_back({-1, num});
      if (!nowIn[num]) countIn++;
      nowIn[num] = false;
    }
  }
  int lastLeft = -1;
  for (int i = (0), ei = (m); i < ei; i++) {
    int cm = moves[i].second;
    if (moves[i].first == -1) {
      countIn--;
      nowIn[cm] = false;
      if (countIn != 0)
        alwaysWas[cm] = false;
      else {
        if (lastLeft != -1) {
          if (lastLeft != cm) {
            alwaysWas[cm] = false;
            alwaysWas[lastLeft] = false;
            lastLeft = llt;
          } else {
          }
        } else
          lastLeft = cm;
      }
    } else {
      nowIn[cm] = true;
      if (countIn != 0)
        alwaysWas[cm] = false;
      else {
        if (lastLeft != -1) {
          if (lastLeft != cm) {
            alwaysWas[cm] = false;
            alwaysWas[lastLeft] = false;
            lastLeft = llt;
          } else {
          }
        } else
          lastLeft = cm;
      }
      countIn++;
    }
  }
  vector<int> res;
  for (int i = (0), ei = (n); i < ei; i++) {
    if (alwaysWas[i]) res.push_back(i + 1);
  }
  printf("%d\n", (int)res.size());
  for (int i = (0), ei = (res.size()); i < ei; i++) {
    printf("%d ", res[i]);
  }
  return false;
}
int main() {
  run();
  return 0;
}
