#include <bits/stdc++.h>
#define for0(i,n) for(int i=0; i<n; i++)
#define for1(i,n) for(int i=1; i<=n; i++)
#define pb push_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define V vector<int>
#define VP vector<pair<int, int> >
#define clr(A,x) memset(A, x, sizeof(A))
#define cpy(A,B) memcpy(A, B, sizeof(B))
#define g(s) getline(cin, s) ///ai grija la fin/cin ///
#define FASTIO ios_base::sync_with_stdio(0)
#define INF 0x3f3f3f3f
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

const int CHARMAX = (1 << 10);
const int INFINT = 2000000000;
const ll INFLL = (1LL << 62);

class InParsare
{
private:
    FILE *fin;
    char *buffer;
    size_t index_of_buffer;

    char read_character()
    {
        index_of_buffer++;
        if(index_of_buffer == CHARMAX)
        {
            fread(buffer, 1, CHARMAX, fin);
            index_of_buffer = 0;
        }
        return buffer[index_of_buffer];
    }

public:
    InParsare(const char *name)
    {
        fin = fopen(name, "r");
        buffer = new char[CHARMAX]();
        index_of_buffer = CHARMAX - 1;
    }

    template<class T>
    InParsare &operator >> (T &n)
    {
        char c;
        while(!isdigit(c = read_character()) && c != '-');

        int sgn = 1;
        if(c == '-')
        {
            n = 0;
            sgn = -1;
        }
        else n = c - '0';

        while(isdigit(c = read_character()))
            n = n * 10 + c - '0';
        n *= sgn;

        return *this;
    }
};

class OutParsare
{
private:
    FILE *fout;
    char *buffer;
    size_t index_of_buffer;

    void write_character(char character)
    {
        if(index_of_buffer == CHARMAX)
        {
            fwrite(buffer, 1, CHARMAX, fout);
            index_of_buffer = 0;
            buffer[index_of_buffer++] = character;
        }
        else buffer[index_of_buffer++] = character;
    }

public:

    OutParsare(const char *name)
    {
        fout = fopen(name, "w");
        buffer = new char[CHARMAX]();
        index_of_buffer = 0;
    }

    ~OutParsare()
    {
        fwrite(buffer, 1, index_of_buffer, fout);
        fclose(fout);
    }
    template<class T>
    OutParsare &operator << (T n)
    {
        if(typeid(T).name() == typeid(char).name())
        {
            write_character(n);
            return *this;
        }

        if(n <= 9)
            write_character(n + '0');
        else
        {
            (*this) << (n / 10);
            write_character(n % 10 + '0');
        }

        return *this;
    }

};

//InParsare fin("nume.in"); /// merg numai pt numere
//OutParsare fout("nume.out"); /// merg numai pt numere + caractere individuale, nu stringuri
ifstream fin("zeap.in");
ofstream fout("zeap.out");

struct node
{
    int mmin, mmax, difmin, key, priority;
    node *left, *right;
};

node* newNode(int key)
{
    node *ret = new node();

    ret -> mmin = ret -> mmax = ret -> key = key;
    ret -> difmin = INFINT;
    ret -> priority = rand();

    ret -> left = ret -> right = NULL;

    return ret;
}

void calculations(node *&nod)
{
    nod -> mmin = nod -> mmax = nod -> key;
    nod -> difmin = INFINT;

    if(nod -> left)
    {
        nod -> mmin = min(nod -> mmin , nod -> left -> mmin);
        nod -> mmax = max(nod -> mmax, nod -> left -> mmax);

        nod -> difmin = min(nod -> difmin, nod -> left -> difmin);
        nod -> difmin = min(nod -> difmin, nod -> key - nod -> left -> mmax);
    }

    if(nod -> right)
    {
        nod -> mmin = min(nod -> mmin , nod -> right -> mmin);
        nod -> mmax = max(nod -> mmax, nod -> right -> mmax);

        nod -> difmin = min(nod -> difmin, nod -> right -> difmin);
        nod -> difmin = min(nod -> difmin, nod -> right -> mmin - nod -> key);
    }
}

node* rotateRight(node *y)
{
    node *x = y -> left , *T2 = x -> right;

    x -> right = y;
    y -> left = T2;

    calculations(y);
    calculations(x);

    return x;
}

node* rotateLeft(node *x)
{
    node *y = x -> right , *T2 = y -> left;

    y -> left = x;
    x -> right = T2;

    calculations(x);
    calculations(y);

    return y;
}

node* insertion(node *nod, int key)
{
    if(nod == NULL)
        return newNode(key);

    if(key < nod -> key)
    {
        nod -> left = insertion(nod -> left, key);

        if(nod -> left -> priority > nod -> priority)
            nod = rotateRight(nod);
    }

    if(key > nod -> key)
    {
        nod -> right = insertion(nod -> right, key);

        if(nod -> right -> priority > nod -> priority)
            nod = rotateLeft(nod);
    }

    calculations(nod);

    return nod;
}

node* removal(node *nod, int key)
{
    if(nod == NULL)
        return nod;

    if(key < nod -> key)
        nod -> left = removal(nod -> left, key);
    else if(key > nod -> key)
        nod -> right = removal(nod -> right, key);
    else if(nod -> left == NULL)
    {
        node *temp = nod -> right;
        delete(nod);
        nod = temp;
    }
    else if(nod -> right == NULL)
    {
        node *temp = nod -> left;
        delete(nod);
        nod = temp;
    }
    else
    {
        if(nod -> left -> priority > nod -> right -> priority)
        {
            nod = rotateRight(nod);
            nod -> right = removal(nod -> right, key);
        }
        else
        {
            nod = rotateLeft(nod);
            nod -> left = removal(nod -> left, key);
        }
    }

    if(nod == NULL)
        return nod;
    calculations(nod);
    return nod;
}

unordered_map<int, bool> contor;

int main()
{
    node *root = NULL;
    string op;
    int a;
    while(fin >> op)
    {
        if(op == "I")
        {
            fin >> a;
            root = insertion(root, a);
            contor[a] = 1;
        }
        else if(op == "S")
        {
            fin >> a;
            if(contor[a])
            {
                contor[a] = 0;
                root = removal(root, a);
            }
            else fout << "-1\n";
        }
        else if(op == "C")
        {
            fin >> a;
            fout << contor[a] << '\n';
        }
        else if(op == "MAX")
            fout << (root -> mmax - root -> mmin == 0 ? -1 : root -> mmax - root -> mmin) << '\n';
        else if(op == "MIN")
            fout << (root -> difmin == INFINT ? -1 : root -> difmin) << '\n';
    }


   return 0;
}