C++ :

#include <cstdio>

using namespace std;

const int SN = 1000000 + 10;

int f[SN], ch[SN][2], key[SN], cnt[SN], size[SN];
int sz, root;

inline void Read(int &x) {
    int in = 0,f = 1;char ch = getchar();
    while(ch<'0' || ch>'9') {if(ch=='-') f = -1;ch = getchar();}
    while(ch>='0' && ch<='9') {in = in*10+ch-'0';ch = getchar();}
    x = in*f;
}

inline void clear(int x){
    f[x] = ch[x][0] = ch[x][1] = key[x] = size[x] = cnt[x] = 0;
}

inline int get(int x){
    return ch[f[x]][1] == x;
}

inline void update(int x) {
    if(x) {
	size[x] = cnt[x];
	if(ch[x][0]) size[x] += size[ch[x][0]];
	if(ch[x][1]) size[x] += size[ch[x][1]];
    }	
}

inline void rotate(int x) {
    int fa = f[x], anc = f[fa], which = get(x);
    ch[fa][which] = ch[x][which^1], f[ch[fa][which]] = fa;
    f[x] = anc, f[fa] = x, ch[x][which^1] = fa;
    if(anc) ch[anc][ch[anc][1] == fa] = x;
    update(fa),update(x);
}

inline void splay(int x) {
    for(int fa;fa = f[x];rotate(x)) 
	if(f[fa]) rotate((get(x)==get(fa))? fa: x);
    root = x;
}

inline int find(int x) {
    int now = root, ans = 0;
    while(1) {
	if(x < key[now]) now = ch[now][0];
	else {
	    ans += ch[now][0]? size[ch[now][0]]: 0;
	    if(x == key[now]) {splay(now);return ans + 1;}
	    ans += cnt[now];
	    now = ch[now][1];
	}
    }
}

inline int findx(int x) {
    int now = root;
    while(1) {
	if(ch[now][0] && x<=size[ch[now][0]]) now = ch[now][0];
	else {
	    int tmp = (ch[now][0]? size[ch[now][0]]: 0) + cnt[now];
	    if(x <= tmp) {return key[now];}
	    x -= tmp;now = ch[now][1];
	}
    }
}

inline int pre() {
    int now = ch[root][0];
    while(ch[now][1]) now = ch[now][1];
    return now;
}

inline int net() {
    int now = ch[root][1];
    while(ch[now][0]) now = ch[now][0];
    return now;
}

inline void insert(int x) {
    if(root == 0) {
	sz++;
	ch[sz][0] = ch[sz][1] = f[sz] = 0;key[sz] = x,root = sz;
	cnt[sz] = size[sz] = 1;
	return ;
    }
    int now = root, fa = 0;
    while(1) {
	if(key[now] == x) {cnt[now]++; update(now); update(fa);splay(now);return ;}
	fa = now;
	now = ch[now][x > key[now]];
	if(now == 0) {
	    sz++;
	    ch[sz][0] = ch[sz][1] = 0;
	    key[sz] = x, ch[fa][x > key[fa]] = sz, cnt[sz] = size[sz] = 1;
	    f[sz] = fa;
	    update(fa);
	    splay(sz);
	    return ;
	}
    }
}    

inline void del(int x) {
    find(x);
    if(cnt[root] > 1) {cnt[root]--; update(root); return ;}
    if(!ch[root][1] && !ch[root][0]) { clear(root),root =0;return ;}
    if(!ch[root][1]) {
	int anc = root; root = ch[root][0];
	f[root] = 0;clear(anc);
	return ;
    }
    else if(!ch[root][0]) {
	int anc = root; root = ch[root][1];
	f[root] = 0; clear(anc);
	return ;
    }
    int left = pre(), anc = root;
    splay(left);
    ch[root][1] = ch[anc][1],f[ch[anc][1]] = root;
    clear(anc);
    update(root);
    return ;
}

int main() {
    int n, x, opt;
    Read(n);
    for(int i = 1; i <= n; i++) {
	Read(opt),Read(x);
	switch(opt) {
	case 1: insert(x);break;
	case 2: del(x);break;
	case 3: printf("%d\n",find(x));break;
	case 4: printf("%d\n",findx(x));break;
	case 5: insert(x),printf("%d\n",key[pre()]),del(x);break;
	case 6: insert(x),printf("%d\n",key[net()]),del(x);break;
	}
    }
    return 0;
}