#include <iostream>

#include <cstdio>

#include <set>

#define REP(i,a,n) for(int i=a;i<=n;++i)

using namespace std;

const int N = 1e6+10;

int n, m, id[N], ans[N];

char op[N];

int main() {

	scanf("%d%d", &n, &m);

	REP(i,1,n) ans[i] = 1;

	int s = 0, t = 0;

	REP(i,1,m) {

		scanf(" %c%d", op+i, id+i);

		if (op[i]=='-'&&ans[id[i]]) t = id[i];

		if (op[i]=='+'&&!s) s = id[i];

		ans[id[i]] = 0;

	}

	set<int> q;

	int leader = t?t:s;

	q.insert(leader);

	ans[leader] = 1;

	REP(i,1,m) {

		if (op[i]=='+') {

			q.insert(id[i]);

			if (!q.count(leader)) ans[leader] = 0;

		}

		else {

			q.erase(id[i]);

			if (q.size()&&!q.count(leader)) ans[leader] = 0;

		}

	}

	int sum = 0;

	REP(i,1,n) sum += ans[i];

	printf("%d\n", sum);

	REP(i,1,n) if (ans[i]) printf("%d ", i);

	puts("");

}