#include <bits/stdc++.h>
int zt[100105];
int a[100105];
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) {
    zt[i] = 1;
    a[i] = 0;
  }
  int z;
  int z1 = 0, zm;
  int rs = 0;
  char str[10];
  for (int i = 1; i <= m; ++i) {
    scanf("%s", str);
    scanf("%d", &z);
    if (str[0] == '-') z = -z;
    if (z > 0) {
      a[z] = 1;
      if (i != 1 && rs != 0) {
        zt[z] = 0;
      }
      if (i == 1) {
        z1 = z;
      }
      if (rs == 0) {
        if (z != z1) {
          zt[z] = 0;
          zt[z1] = 0;
        }
      }
      rs++;
    }
    if (z < 0) {
      if (a[-z] == 0) {
        a[-z] = 2;
        zt[z1] = 0;
        z1 = -z;
      } else {
        rs--;
        a[-z] = 3;
      }
      if (i != m && rs != 0) {
        zt[-z] = 0;
      }
      if (i == m) {
        zm = -z;
        for (int j = 1; j <= n; ++j) {
          if (a[j] == 1) {
            zt[zm] = 0;
            break;
          }
        }
      }
    }
  }
  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    if (zt[i] == 1) {
      ans++;
    }
  }
  printf("%d\n", ans);
  for (int i = 1; i <= n; ++i) {
    if (zt[i] == 1) {
      printf("%d ", i);
    }
  }
  return 0;
}
