#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cctype>
#define mid ((l+r)>>1)
#define left (rt<<1)
#define right (rt<<1|1)
#define lson l,mid,left
#define rson mid+1,r,rightusing std::max;
using std::min;inline int read(){int num=0,f=1;char ch=getchar();while(!isdigit(ch)){if(ch=='-')    f=-1;ch=getchar();}while(isdigit(ch)){num=num*10+ch-'0';ch=getchar();}return num*f;
}int s[502000];
int q[102000];struct Node{int e[2],fa,val,size,sum;
}tree[5002000];
int tot,point;
inline void update(int x){tree[x].size=tree[x].sum;if(tree[x].e[0])    tree[x].size+=tree[tree[x].e[0]].size;if(tree[x].e[1])    tree[x].size+=tree[tree[x].e[1]].size;
}
inline void connect(int x,int fa,int how){    tree[x].fa=fa;    tree[fa].e[how]=x;    }
inline int iden(int x){    return x==tree[tree[x].fa].e[1];    }
void rotate(int x,int rt){int y=tree[x].fa;    int r=tree[y].fa;if(y==s[rt])    s[rt]=x;int sony=iden(x);    int sonr=iden(y);int b=tree[x].e[sony^1];connect(b,y,sony);connect(y,x,sony^1);connect(x,r,sonr);update(y);    update(x);
}void splay(int pos,int to,int rt){to=tree[to].fa;while(tree[pos].fa!=to){if(tree[tree[pos].fa].fa==to)    rotate(pos,rt);elseif(iden(pos)==iden(tree[pos].fa)){    rotate(tree[pos].fa,rt);    rotate(pos,rt);    }else    {    rotate(pos,rt);    rotate(pos,rt);    }}
}inline int create(int val,int fa){tree[++tot].val=val;tree[tot].fa=fa;tree[tot].sum=tree[tot].size=1;return tot;
}inline void Delete(int x){tree[x].e[0]=tree[x].e[1]=0;if(x==tot)    tot--;
}int build(int val,int rt){point++;if(!s[rt]){    s[rt]=create(val,0);    return s[rt];}else{int now=s[rt];while(1){tree[now].size++;if(val==tree[now].val){    tree[now].sum++;    return now;    }int nxt=val<tree[now].val?0:1;if(!tree[now].e[nxt]){create(val,now);tree[now].e[nxt]=tot;return tot;}now=tree[now].e[nxt];}}return 0;
}inline void insert(int val,int rt){int p=build(val,rt);splay(p,s[rt],rt);
}int find(int val,int rt){int now=s[rt];while(now){if(tree[now].val==val){    splay(now,s[rt],rt);    return now;    }int nxt=val>tree[now].val;if(!tree[now].e[nxt])    return 0;now=tree[now].e[nxt];}
}void pop(int val,int rt){int deal=find(val,rt);if(!deal)    return;point--;if(tree[deal].sum>1){    tree[deal].sum--;    tree[deal].size--;    return;    }if(!tree[deal].e[0]){    s[rt]=tree[deal].e[1];    tree[s[rt]].fa=0;    }else{int le=tree[deal].e[0];while(tree[le].e[1])    le=tree[le].e[1];splay(le,tree[deal].e[0],rt);int ri=tree[deal].e[1];connect(ri,le,1);    s[rt]=le;update(le);}Delete(deal);
}int rank(int val,int rt){int ans=0,now=s[rt];while(1){//printf("%d %d\n",now,tree[now].sum);if(val<tree[now].val){now=tree[now].e[0];if(!now)    return ans;}else{if(tree[now].e[0])    ans+=tree[tree[now].e[0]].size;if(val==tree[now].val||!tree[now].e[1]){if(val>tree[now].val)    ans+=tree[now].sum;splay(now,s[rt],rt);return ans;}ans+=tree[now].sum;    now=tree[now].e[1];}}
}inline int lower(int val,int rt){int ans=-2147483647,now=s[rt];while(1){if(!now)    return ans;if(tree[now].val<val&&tree[now].val>ans)    ans=tree[now].val;int nxt=val>tree[now].val?1:0;now=tree[now].e[nxt];}
}inline int upper(int val,int rt){int ans=2147483647,now=s[rt];while(1){if(!now)    return ans;if(tree[now].val>val&&tree[now].val<ans)    ans=tree[now].val;int nxt=val>tree[now].val?1:0;now=tree[now].e[nxt];}
}int lows(int val,int rt){int ans=-2147483647,now=s[rt];while(1){if(!now)    return ans;if(tree[now].val<=val&&tree[now].val>ans)    ans=tree[now].val;if(tree[now].val==val)    return ans;int nxt=val>tree[now].val?1:0;now=tree[now].e[nxt];}
}void Build(int l,int r,int rt){if(l>r)    return;if(l==r){insert(q[l],rt);return;}Build(lson);Build(rson);for(int i=l;i<=r;++i)    insert(q[i],rt);return;
}int findrank(int from,int to,int num,int l,int r,int rt){if(from<=l&&to>=r)    return rank(num,rt);int ans=0;if(from<=mid)    ans+=findrank(from,to,num,lson);if(to>mid)        ans+=findrank(from,to,num,rson);return ans;
}void Update(int o,int num,int l,int r,int rt){pop(q[o],rt);insert(num,rt);if(l==r)    return;if(o<=mid)    Update(o,num,lson);else        Update(o,num,rson);
}int findlower(int from,int to,int num,int l,int r,int rt){if(from<=l&&to>=r)    return lower(num,rt);int ans=-2147483647;if(from<=mid)    ans=max(ans,findlower(from,to,num,lson));if(to>mid)        ans=max(ans,findlower(from,to,num,rson));return ans;
}int findupper(int from,int to,int num,int l,int r,int rt){if(from<=l&&to>=r)    return upper(num,rt);int ans=2147483647;if(from<=mid)    ans=min(ans,findupper(from,to,num,lson));if(to>mid)        ans=min(ans,findupper(from,to,num,rson));return ans;
}int main(){int n=read(),m=read();for(int i=1;i<=n;++i)    q[i]=read();Build(1,n,1);for(register int i=1;i<=m;++i){int opt=read();if(opt==1){int l=read(),r=read(),q=read();printf("%d\n",findrank(l,r,q,1,n,1)+1);}else if(opt==2){int l=read(),r=read(),q=read();int a=0,b=1e8,Ans=0;while(a<=b){int m=(a+b)>>1;int x=lows(m,1);if(findrank(l,r,x,1,n,1)+1>q)    b=m-1;else{a=m+1;Ans=x;}}printf("%d\n",Ans);}else if(opt==3){int l=read(),r=read();Update(l,r,1,n,1);q[l]=r;}else if(opt==4){int l=read(),r=read(),q=read();printf("%d\n",findlower(l,r,q,1,n,1));}else if(opt==5){int l=read(),r=read(),q=read();printf("%d\n",findupper(l,r,q,1,n,1));}}return 0;
}