# 420B

## Solution

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;

#define MAX_MSG_NUM 100005
#define MAX_PEOPEL_NUM 100005
#define D(x)

struct Msg
{
int id;
bool on;
}msg[MAX_MSG_NUM];

int people_num, msg_num;
bool vis[MAX_PEOPEL_NUM];
bool wait[MAX_PEOPEL_NUM];
int init_num;
int ans[MAX_PEOPEL_NUM];

void input()
{
scanf("%d%d", &people_num, &msg_num);
for (int i = 0; i < msg_num; i++)
{
char st[2];
int a;
scanf("%s%d", st, &a);
msg[i].on = (st[0] == '+');
msg[i].id = a - 1;
}
}

void make_wait()
{
memset(vis, 0, sizeof(vis));
memset(wait, 0, sizeof(wait));
bool did = false;
init_num = 0;
for (int i = 0; i < msg_num; i++)
{
if (vis[msg[i].id])
{
continue;
}
if (!msg[i].on)
{
wait[msg[i].id] = true;
init_num++;
did = true;
}
vis[msg[i].id] = true;
}
if (!did)
{
wait[msg[0].id] = true;
}
}

void work()
{
int on_num = init_num;
for (int i = 0; i < msg_num; i++)
{
D(printf("%d %d\n", i, on_num);)
if (msg[i].on)
{
on_num++;
if (on_num == 1 && !wait[msg[i].id])
{
memset(wait, 0, sizeof(wait));
}
continue;
}
on_num--;
if (!wait[msg[i].id])
{
continue;
}
if (on_num > 0)
{
wait[msg[i].id] = false;
}
}
}

void output()
{
int ans_num = 0;
for (int i = 0; i < people_num; i++)
{
if (wait[i] || !vis[i])
{
ans[ans_num++] = i + 1;
D(printf("i = %d\tans = %d\n", i, ans[ans_num - 1]);)
}
}
printf("%d\n", ans_num);
if (ans_num == 0)
return;
printf("%d", ans[0]);
for (int i = 1; i < ans_num; i++)
{
printf(" %d", ans[i]);
}
puts("");
}

int main()
{
input();
make_wait();
work();
output();
return 0;
}