#include <bits/stdc++.h>
using namespace std;

const int MAXN = 100005;


struct Seg {
    int c[MAXN];
    int maxn;

    int lowbit(int x) {return x&(-x);}

    void add(int x, int v) {
        for (; x<=maxn; x+=lowbit(x)) c[x]+=v; 
    }

    int qry(int x) {
        int ret = 0;
        if (x <= 0 || x > maxn) return 0;
        for (; x; x-=lowbit(x)) ret += c[x];
        return ret;
    }

    int qry_between(int l, int r) {
        if (l > r) return 0;
        return qry(r) - qry(l-1);
    }
} seg;



void solve()
{
    int n, q, a, b;
    cin >>n >>q;
    char op[2];
    seg.maxn = n;
    while (q--) {
        cin >>op;
        if (*op == '-') {
            cin >>a;
            seg.add(a, 1);
        }
        else if (*op == '+') {
            cin >>a;
            seg.add(a, -1);
        }
        else {
            cin >>a >>b;
            if (a > b) swap(a, b);
            bool valid = false;
            valid |= (seg.qry_between(a, b) == 0);
            valid |= (seg.qry_between(1, a) == 0 && seg.qry_between(b, n) == 0);
            cout <<(valid ? "possible" : "impossible") <<"\n";
        }
    }
    
}



int main()
{
    solve();
    return 0;
}