#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline string toString(T a) {
  ostringstream os("");
  os << a;
  return os.str();
}
template <typename T>
inline long long toLong(T a) {
  long long res;
  istringstream os(a);
  os >> res;
  return res;
}
template <typename T>
inline T S(T a) {
  return a * a;
}
template <typename T>
inline T gcd(T a, T b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
template <typename T>
inline unsigned long long bigmod(T a, T b, T m) {
  if (b == 0)
    return 1;
  else if (b % 2 == 0)
    return S(bigmod(a, b / 2, m)) % m;
  else
    return (a % m * bigmod(a, b - 1, m)) % m;
}
template <typename T>
inline vector<string> parse(T str) {
  vector<string> res;
  string s;
  istringstream os(str);
  while (os >> s) res.push_back(s);
  return res;
}
template <typename T>
inline unsigned long long dist(T A, T B) {
  unsigned long long res =
      (A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y);
  return res;
}
template <typename T>
inline double cosAngle(T a, T b, T c) {
  double res = a * a + b * b - c * c;
  res = res / (2 * a * b);
  res = acos(res);
  return res;
}
template <typename T>
inline T power(T base, int po) {
  T res = 1;
  if (base == 0) return 0;
  for (int i = (0); i < (po); i++) res *= base;
  return res;
}
template <typename T>
inline bool isOn(T mask, T pos) {
  return mask & (1 << pos);
}
template <typename T>
inline int Off(T mask, T pos) {
  return mask ^ (1 << pos);
}
template <typename T>
inline int On(T mask, T pos) {
  return mask | (1 << pos);
}
vector<string> s1, s2;
vector<int> a, b;
bool on[100005];
bool off[100005];
int main() {
  int i, j, k;
  int x, y;
  int ks, cas;
  int n, m;
  cin >> n >> m;
  char str[3];
  for (i = 0; i < m; i++) {
    scanf("%s", str);
    scanf("%d", &x);
    s1.push_back(str);
    a.push_back(x);
  }
  for (i = 0; i < m; i++) {
    if (s1[i][0] == '+') {
      on[a[i]] |= 1;
    }
    if (s1[i][0] == '-' && on[a[i]] == 0) {
      b.push_back(a[i]);
    }
  }
  int cur = b.size();
  for (i = 0; i < m; i++) {
    if (s1[i][0] == '+') {
      if (cur > 0) {
        off[a[i]] |= 1;
      } else if (cur == 0 && i != 0 && a[i - 1] != a[i]) {
        off[a[i]] = 1;
      }
      cur++;
    } else if (s1[i][0] == '-') {
      if (cur > 1) {
        off[a[i]] = 1;
      } else if (cur == 1 && i < m - 1 && a[i + 1] != a[i]) {
        off[a[i]] = 1;
      }
      cur--;
    }
  }
  int cnt = 0;
  for (i = 1; i <= n; i++) {
    if (off[i] == 0) {
      cnt++;
    }
  }
  cout << cnt << endl;
  for (i = 1; i <= n; i++) {
    if (off[i] == 0) {
      printf("%d ", i);
    }
  }
  printf("\n");
  return 0;
}
