#include <bits/stdc++.h>

using namespace std;

ifstream fin("zeap.in");
ofstream fout("zeap.out");
struct TreapNode {
    int val, pri;
    TreapNode* le;
    TreapNode* ri;

    int mi, ma, miDiff;
};

TreapNode* nullNode;

TreapNode* tRoot;
string s;
int n;

static inline void Build(
    TreapNode* node,
    int _val,
    TreapNode* _le = nullptr,
    TreapNode* _ri = nullptr,
    int _pri = rand() % 10000
) {
    node->val = _val;
    node->pri = _pri;
    node->le = _le;
    node->ri = _ri;
    node->mi = _val;
    node->ma = _val;
    node->miDiff = 1e9;
}

static inline void RotToLe(TreapNode*& node) {
    TreapNode* le = node->le;
    node->le = le->ri;
    le->ri = node;
    node = le;
}

static inline void RotToRi(TreapNode*& node) {
    TreapNode* ri = node->ri;
    node->ri = ri->le;
    ri->le = node;
    node = ri;
}

static inline void Process(TreapNode* node) {
    if(node == nullNode) return;

    node->mi = node->val;
    node->ma = node->val;
    node->miDiff = INT_MAX;
    if(node->le != nullNode) {
        node->mi = node->le->mi;

        node->miDiff = min({
            node->miDiff,
            node->le->miDiff,
            node->val - node->le->ma
        });
    }
    if(node->ri != nullNode) {
        node->ma = node->ri->ma;
        node->miDiff = min({
            node->miDiff,
            node->ri->miDiff,
            node->ri->mi - node->val
        });
    }
}

static inline void Split(TreapNode*& node) {
    if(node == nullNode) return;
    if(node->pri < node->le->pri) RotToLe(node);
    if(node->pri < node->ri->pri) RotToRi(node);
    Process(node->le);
    Process(node->ri);
    Process(node);
}

static inline void Add(TreapNode*& node, int val) {
    if(node == nullNode) {
        node = new TreapNode;
        Build(node, val, nullNode, nullNode);
        return;
    }
    if(val <= node->val) Add(node->le, val);
    else                 Add(node->ri, val);
    Split(node);
}

static inline void Del(TreapNode*& node, int val) {
         if(val < node->val) Del(node->le, val);
    else if(val > node->val) Del(node->ri, val);
    else {
        if(node->le == nullNode && node->ri == nullNode) {
            delete node;
            node = nullNode;
            return;
        }
        if(node->le->pri < node->ri->pri) RotToRi(node);
        else                              RotToLe(node);
        Add(node, val);
    }
    Split(node);
}

static inline bool Search(TreapNode* node, int val) {
    if(node == nullNode) return false;
    if(node->val == val) return true;
    if(node->val >  val) return Search(node->le, val);
    else                 return Search(node->ri, val);
}

static inline int MiDiff(TreapNode* node) {
    if(node == nullNode || node->miDiff == INT_MAX) return -1;
    return node->miDiff;
}

static inline int MaDiff(TreapNode* node) {
    if(node == nullNode) return -1;
    return node->ma - node->mi;
}

int main() {
    fin.tie(nullptr);
    fout.tie(nullptr);

    srand(time(0));

    nullNode = new TreapNode;
    Build(nullNode, 0, nullptr, nullptr, 0);

    tRoot = nullNode;
    while(fin >> s) {
        if(s == "I" || s == "S" || s == "C") fin >> n;

        if(s == "I") Add(tRoot, n);
        else if(s == "S") {
            if(Search(tRoot, n)) Del(tRoot, n);
            else fout << "-1\n";
        }
        else if(s == "C"  ) fout << Search(tRoot, n) << "\n";
        else if(s == "MIN") fout << MiDiff(tRoot   ) << "\n";
        else if(s == "MAX") fout << MaDiff(tRoot   ) << "\n";
    }

    return 0;
}