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

struct nod{
	int v, M, m, d, p;
	nod *l, *r; } *nil = new nod{0, (int)-2e9, (int)2e9, (int)2e9, 0, 0, 0 };

using ns = nod*;
struct pns { ns l, r };

ns mod_fiu(ns b, int s, ns f){
	(s ? b->r : b->l) = f;
	b->M = max({b->v, b->l->M, b->r->M});
	b->m = min({b->v, b->l->m, b->r->m});
	b->d = min({(ll)b->v - b->l->M, (ll)b->r->m - b->v, (ll)b->l->d , (ll)b->r->d });
	return b; };

ns join(ns l, ns r){
	return l == nil      ? r :
		   r == nil      ? l : 
		   (l->p > r->p) ? mod_fiu(l, 1, join(l->r, r   )) :
						   mod_fiu(r, 0, join(l   , r->l)); }

pns split(ns n, int m){
	pns t;
	return (n->M < m)  ? pns(n, nil) :
		   (n->m >= m) ? pns(nil, n) :
		   (n->v < m)  ? (t = split(n->r, m), t.l = mod_fiu(n, 1, t.l), t) :
						 (t = split(n->l, m), t.r = mod_fiu(n, 0, t.r), t); }

ns r = nil;

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

int main(){
	srand(time(0));
	for(string s; f >> s; ){
		if     (s == "MAX") g << (r->M <= r->m ? -1 : r->M - r->m) << '\n';
		else if(s == "MIN") g << (r->M <= r->m ? -1 : r->d       ) << '\n';
		else{
			int x;
			f >> x;
			pns t = split(r, x), u = split(t.r, x+1);
			if(s == "I")
				r = join(join(t.l,
					(u.l == nil ? new nod { x, x, x, (int)2e9, rand(), nil, nil } : u.l)),
					u.r);
			else if(s == "S"){
				if(u.l == nil) g << -1 << '\n';
				else delete u.l;
				r = join(t.l, u.r); }
			else{
				g << (u.l != nil) << '\n';
				r = join(join(t.l, u.l), u.r); } } }
	return 0; }