#include <bits/stdc++.h>

using namespace std;

ifstream fin("zeap.in");
ofstream fout("zeap.out");

mt19937 mt(time(0));

const int inf=2e9;

struct nod{
    int key;
    int pr;
    int cnt;
    int mx;
    int mn;
    int dif;
    nod *l, *r;
    nod(int x):key(x),pr(mt()),cnt(1),mx(x),mn(x),dif(inf),l(NULL),r(NULL){}
};

typedef nod* treap;

treap root;

int cnt(treap t)
{
    if(t)return t->cnt;
    return 0;
}

int mx(treap t)
{
    if(t)return t->mx;
    return 0;
}

int mn(treap t)
{
    if(t)return t->mn;
    return inf;
}

int dif(treap t)
{
    if(t)return t->dif;
    return inf;
}

void upd(treap &t)
{
    if(!t)return;
    t->cnt = cnt(t->l)+cnt(t->r)+1;
    t->mx = max(t->key,mx(t->r));
    t->mn = min(t->key,mn(t->l));
    t->dif = min(dif(t->l),dif(t->r));
    if(t->l)t->dif = min(t->dif,t->key-mx(t->l));
    if(t->r)t->dif = min(t->dif,mn(t->r)-t->key);
}

void split(treap t, treap &st, treap &dr, int x)
{
    if(!t)
    {
        st=dr=NULL;
        return;
    }
    if(t->key<=x)
        split(t->r,t->r,dr,x),st=t;
    else split(t->l,st,t->l,x),dr=t;
    upd(t);
    upd(st);
    upd(dr);
}

void mer(treap &t, treap st, treap dr)
{
    if(!st)t=dr;
    else if(!dr)t=st;
    else if(st->pr>=dr->pr)
        mer(st->r,st->r,dr),t=st;
    else mer(dr->l,st,dr->l),t=dr;
    upd(t);
    upd(st);
    upd(dr);
}

bool cauta(treap t, int x)
{
    if(!t)return 0;
    if(t->key==x)return 1;
    if(t->key>x)return cauta(t->l,x);
    return cauta(t->r,x);
}

void ins(int x)
{
    if(cauta(root,x))return;
    treap maimic;
    treap maimare;
    treap egal = new nod(x);
    split(root,maimic,maimare,x-1);
    mer(maimic,maimic,egal);
    mer(maimic,maimic,maimare);
    root = maimic;
}

void sterge(int x)
{
    if(!cauta(root,x)){fout<<-1<<'\n';return;}
    treap maimic;
    treap maimare;
    treap trash;
    split(root,maimic,maimare,x-1);
    split(maimare,trash,maimare,x);
    mer(root,maimic,maimare);
}

void maxdif()
{
    if(cnt(root)<2){fout<<-1<<'\n';return;}
    fout<<mx(root)-mn(root)<<'\n';
}

void mindif()
{
    if(cnt(root)<2){fout<<-1<<'\n';return;}
    fout<<dif(root)<<'\n';
}

string s;
int nr;

signed main()
{
    while(fin>>s)
    {
        if(s=="MAX")maxdif();
        else if(s=="MIN")mindif();
        else {
            fin>>nr;
            if(s=="I")ins(nr);
            else if(s=="S")sterge(nr);
            else fout<<cauta(root,nr)<<'\n';
        }
    }
    return 0;
}