#include <bits/stdc++.h>

using namespace std;

const int sqrInf = (1e9) - 1;

struct nod
{
    int mn, mx;
    int dn;
    int pr, nr;
    nod *fst = NULL, *fdr = NULL;

    nod(int _mn, int _mx, int _dn, int _pr, int _nr) : mn(_mn), mx(_mx), dn(_dn), pr(_pr), nr(_nr){}

    nod(){}
};

nod *nil;
nod *rad;

int Q;

bool p(int nr)
{
    return (Q > nr);
}

nod *mfiu(nod *n, int care, nod *fiu){
    (care == 0 ? n->fst : n->fdr) = fiu;
    n->mx = max({n->fst->mx, n->fdr->mx, n->nr});
        n->mn = min({n->fst->mn, n->fdr->mn, n->nr});
    n->dn = min({n->fst->dn, n->fdr->dn, n->fdr->mn - n->nr, n->nr - n->fst->mx });
    return n;
}

pair <nod*, nod*> split(nod *n)
{
    if(n == nil)
        return {nil, nil};

    if(p(n -> nr))
    {
        auto tmp = split(n -> fdr);
        mfiu(n, 1, tmp.first);
        return {n, tmp.second};
    }

    else
    {
        auto tmp = split(n -> fst);
        mfiu(n, 0, tmp.second);
        return {tmp.first, n};
    }
}

nod *join(nod *st, nod *dr)
{
    if(st == nil)
        return dr;

    if(dr == nil)
        return st;

    if((st -> pr) > (dr -> pr))
        return mfiu(st, 1, join(st -> fdr, dr));

    else
        return mfiu(dr, 0, join(st, dr -> fst));
}

string x;

void ansQues()
{
    rad = nil;
    int cnt = 0;

    srand(time(0));

    ifstream f("zeap.in");
    ofstream g("zeap.out");

    while(f >> x)
    {
        if(x.size() < 1)
            break;

        if(!(x[0] >= 'A' && x[0] <= 'Z'))
            break;

        if(x.size() == 1)
        {
            int val;
            f >> val;

            nod *nou;
            if(x == "I")
            {
                nou = new nod;
                nou -> pr = rand();
                nou -> mx = nou -> mn = nou -> nr = val;
                nou -> fst = nou -> fdr = nil;
                nou -> dn = sqrInf;
            }

            /*if(rad == nil)
            {
                rad = nou;
                continue;
            }*/

            Q = val;
            auto tmp = split(rad);

           // cout << " SPLIT DUPA " << val << " " << tmp.first << " = " << (tmp.first != nil ? tmp.first -> nr : 0)
            //                          << " +++ " << tmp.second << " = " << (tmp.second != nil ? tmp.second -> nr : 0) << "\n";

            Q = val + 1;
            auto tmp2 = split(tmp.second);

            if(x == "I")
            {
                if(tmp2.first == nil)
                    tmp2.first = nou, cnt ++;
            }

            if(x == "C")
                g << (tmp2.first == nil ? 0 : 1) << "\n";

            if(x == "S")
            {
              //  cout << " SUNTEM STERGEM " << val << " " << tmp2.first << " " << (tmp2.first != nil ? tmp2.first -> nr : 0) << "\n";

                if(tmp2.first == nil)
                    g << "-1\n";

                else
                {
                    delete tmp2.first;
                    tmp2.first = nil;
                    cnt --;
                }
            }

            rad = join(tmp.first, join(tmp2.first, tmp2.second));
        }

        else
        {/*
            if(x == "MAX")
            {
                cout << " MXXXXX" << rad -> dx << " r " << rad -> nr << " n " << rad -> mn << " x " << rad -> mx << "\n";
            }*/

           // cout << ": AVEM RAD " << rad -> dn << " " << rad -> dx << "\n";

           // cout << x << " ESTE " << (x == "MAX") << " SAU " << (x == "MIN") << "\n";

            if(x == "MAX")
                g << (cnt > 1 ? rad -> mx - rad -> mn : -1) << "\n";

            if(x == "MIN")
            {
               // cout << " FAIAFINFSAIF MI FMFM IM " << rad -> dn << "\n";

                g << (cnt > 1 ? rad -> dn : -1) << "\n";
            }
        }

       // cout << rad << " RADDDDDD " << rad -> nr << "\n";
    }

    f.close();
    g.close();
}

int main()
{
    nil = new (nod) { (int)1e9, (int)-1e9, (int)1e9, 0, 0 };

    ansQues();

    return 0;
}