#include<cstdio>

 #include<iostream>

 #define outd(x) printf("%d\n",x)

 #define outld(x) printf("%lld\n", x)

 #define ls(x)  arr[x].child[0]

 #define rs(x)  arr[x].child[1]

 inline int read_int()

 {

     char c;

     int ret = , sgn = ;

     do { c = getchar(); } while ((c < '' || c > '') && c != '-');

     if (c == '-')  sgn = -;  else ret = c - '';

     while ((c = getchar()) >= '' && c <= '')  ret = ret *  + (c - '');

     return sgn * ret;

 }

 using namespace std;

 const int maxn =  + ;

 struct node

 {

     int child[], size, value, key;

 }arr[maxn];

 int tot;     //当前节点个数

 inline void push_up(int index)

 {

     arr[index].size = arr[ls(index)].size + arr[rs(index)].size + ;

 }

 void split(int root, int& x, int& y, int value)  //x中的小于或等于value，y中的大于value

 {

     if (!root) { x = y = ; return; }

     if (arr[root].value <= value) { x = root; split(rs(root), rs(x), y, value); }

     else { y = root; split(ls(root), x, ls(y), value); }

     push_up(root);

 }

 void merge(int&root, int x, int y)

 {

     if (!x || !y) { root = x + y; return; }     //其中一个为0，root等于另一个

     if (arr[x].key < arr[y].key) { root = x; merge(rs(root), rs(x), y); }

     else { root = y; merge(ls(root), x,ls(y)); }

     push_up(root);

 }

 inline void insert(int& root, int value)

 {

     int x = , y = , z = ++tot;

     arr[z].value = value, arr[z].size = , arr[z].key = rand();

     split(root, x, y, value);

     merge(x, x, z);

     merge(root, x, y);

 }

 inline void erase(int& root, int value)

 {

     int x = , y = , z = ;

     split(root, x, y, value);

     split(x, x, z, value - );        //z中全是value

     merge(z, ls(z), rs(z));

     merge(x, x, z);

     merge(root, x, y);

 }

 inline int Kth_number(int root, int k)

 {

     while (arr[ls(root)].size +  != k)

     {

         if (arr[ls(root)].size >= k)  root = ls(root);

         else { k -= (arr[ls(root)].size + ); root = rs(root); }

     }

     return arr[root].value;

 }

 inline int Get_rank(int& root, int value)

 {

     int x = , y = ;

     split(root, x, y, value - );

     int res = arr[x].size + ;

     merge(root, x, y);

     return res;

 }

 inline int Pre(int& root, int value)

 {

     int x = , y = ;

     split(root, x, y, value - );

     int res = Kth_number(x, arr[x].size);

     merge(root, x, y);    //merge回去

     return res;

 }

 inline int Suf(int& root, int value)

 {

     int x = , y = ;

     split(root, x, y,value);

     int res = Kth_number(y, );

     merge(root, x, y);

     return res;

 }

 int n, op, root;

 int main()

 {

     srand();

     n = read_int();

     while (n--)

     {

         op = read_int();

         if (op == )  insert(root, read_int());

         if (op == )  erase(root, read_int());

         if (op == )  outd(Get_rank(root, read_int()));

         if (op == )  outd(Kth_number(root, read_int()));

         if (op == )  outd(Pre(root, read_int()));

         if (op == )  outd(Suf(root, read_int()));

     }

     return ;

 }