#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#define maxn 5000010
#define ls son[u][0]
#define rs son[u][1]
#define rks son[rk][0]
#define m (l+r>>1)
#define s0 siz[0]=0
#define Ls (n<<1)
#define Rs (n<<1|1)
#define inf 2147483647
#define rep(i,x,y) for(register int i=(x);i<=(y);i++)
#define dwn(i,x,y) for(register int i=(x);i>=(y);i--)
using namespace std;
inline int read()
{int x=0,f=1;char ch=getchar();while(isdigit(ch)==0 && ch!='-')ch=getchar();if(ch=='-')f=-1,ch=getchar();while(isdigit(ch))x=x*10+ch-'0',ch=getchar();return x*f;
}
inline void write(int x)
{int f=0;char ch[20];if(!x){putchar('0'),putchar('\n');return;}if(x<0){putchar('-');x=-x;}while(x)ch[++f]=x%10+'0',x/=10;while(f)putchar(ch[f--]);putchar('\n');
}
int rt[maxn],fa[maxn],son[maxn][3],key[maxn],num[maxn],siz[maxn],a[maxn],cnt,nn,x,y,rank;
inline void pu(int u){s0,siz[u]=siz[ls]+siz[rs]+num[u],s0;}
inline int res(int k,int f){key[++cnt]=k,fa[cnt]=f,num[cnt]=1;return cnt;}
inline int getso(int u){return son[fa[u]][0]!=u;}
inline void rot(int u)
{int fu=fa[u],ffu=fa[fu],l=getso(u),r=l^1,fl=getso(fu),rson=son[u][r];fa[rson]=fu,fa[u]=ffu,fa[fu]=u,son[u][r]=fu,son[fu][l]=rson,son[ffu][fl]=u;pu(fu),pu(u);
}
inline void splay(int u,int k,int pla)
{while(fa[u]!=k){int fu=fa[u];if(fa[fu]!=k)rot(getso(u)^getso(fu)?u:fu);rot(u);}if(!k)rt[pla]=u;
}
inline void fnd(int k,int pla)
{int u=rt[pla];while(son[u][k>key[u]]&&k!=key[u])u=son[u][k>key[u]];splay(u,0,pla);
}
inline int nxt(int k,int f,int pla)
{fnd(k,pla);int u=rt[pla];if((key[u]>k&&f)||(key[u]<k&&!f))return u;u=son[u][f];while(son[u][f^1])u=son[u][f^1];return u;
}
inline void ins(int k,int pla)
{int lk=nxt(k,0,pla),rk=nxt(k,1,pla);splay(lk,0,pla),splay(rk,lk,pla);if(rks)num[rks]++;else rks=res(k,rk);pu(rks),pu(rk),pu(lk);
}
inline void sgtr(int n,int l,int r)
{rt[n]=res(-inf,0);son[rt[n]][1]=res(inf,rt[n]);pu(son[rt[n]][1]),pu(rt[n]);rep(i,l,r)ins(a[i],n);if(l==r)return;sgtr(Ls,l,m),sgtr(Rs,m+1,r);
}
inline int rnk(int k,int pla)
{int u=rt[pla],rank=0;while(u){if(key[u]==k){rank+=siz[ls];break;}if(key[u]<k)rank+=siz[ls]+num[u],u=rs;else u=ls;}return rank-1;
}
inline void del(int k,int pla)
{int lk=nxt(k,0,pla),rk=nxt(k,1,pla);splay(lk,0,pla),splay(rk,lk,pla);if(num[rks]>1)num[rks]--;else rks=0;pu(rks),pu(rk),pu(lk);
}
inline int _1(int n,int l,int r,int k)
{//getrankif(x<=l&&r<=y)return rnk(k,n);if(y<l||r<x)return 0;int lans=_1(Ls,l,m,k),rans=_1(Rs,m+1,r,k);return lans+rans;
}
inline int _2(int k)
{//kthint l=0,r=100000001;while(l!=r){rank=_1(1,1,nn,m)+1;if(rank>k) r=m;else l=m+1;}return l-1;
}
inline void _3(int n,int l,int r,int k)
{//changeif(x<l||r<x)return;del(a[x],n),ins(k,n);if(l==r)return;_3(Ls,l,m,k),_3(Rs,m+1,r,k);if(n==1)a[x]=k;
}
inline int _4(int n,int l,int r,int k)
{//prefixif(x<=l&&r<=y)return key[nxt(k,0,n)];if(y<l||r<x)return -inf;int lans=_4(Ls,l,m,k),rans=_4(Rs,m+1,r,k);return max(lans,rans);
}
inline int _5(int n,int l,int r,int k)
{//suffixif(x<=l&&r<=y)return key[nxt(k,1,n)];if(y<l||r<x)return inf;int lans=_5(Ls,l,m,k),rans=_5(Rs,m+1,r,k);return min(lans,rans);
}
int main()
{int n,q,f,c;nn=n=read(),q=read();rep(i,1,n)a[i]=read();sgtr(1,1,n);while(q--){f=read(),x=read(),y=read(),c;if(f==1)c=read(),write(_1(1,1,n,c)+1);if(f==2)c=read(),write(_2(c));if(f==3)_3(1,1,n,y);if(f==4)c=read(),write(_4(1,1,n,c));if(f==5)c=read(),write(_5(1,1,n,c));}return 0;
}