#include<cmath>
#include<cstdio>
#include<algorithm>
#define inf (2147483647)
using namespace std;
const int N=5e4+50;
struct FK {int l,r;} K[500];
int n,m,T,sqr,ans,a[N],b[N],fa[N];
void work1(int l,int r,int x)
{ans=0; if(fa[l]==fa[r]||fa[l]+1==fa[r]){for(int i=l;i<=r;i++) if(a[i]<x) ans++; return ;}for(int i=l;i<=K[fa[l]].r;i++) if(a[i]<x) ans++;for(int k=fa[l]+1;k<fa[r];k++){int L=K[k].l,R=K[k].r,res,mid;if(b[L]>=x) continue; while(L<=R){mid=(L+R)>>1; if(b[mid]<x) res=mid,L=mid+1; else R=mid-1;} ans+=(res-K[k].l+1); // 这里写成了 ans+=(res-L+1);L已经改变所以是错的。。。
    }for(int i=K[fa[r]].l;i<=r;i++) if(a[i]<x) ans++;
}
int work2(int l,int r,int x)  // 最大的不成立值的就是要找的答案
{int L=0,R=1e9,mid,res=0;while(L<=R){mid=(L+R)>>1; work1(l,r,mid);if(ans<x) res=mid,L=mid+1; else R=mid-1;} return res;
}
void work4(int l,int r,int x)
{ans=-inf; if(fa[l]==fa[r]||fa[l]+1==fa[r]){for(int i=l;i<=r;i++) if(a[i]<x&&a[i]>ans) ans=a[i]; return ;}for(int i=l;i<=K[fa[l]].r;i++) if(a[i]<x&&a[i]>ans) ans=a[i];for(int k=fa[l]+1;k<fa[r];k++){int L=K[k].l,R=K[k].r,res,mid;if(b[L]>=x) continue; while(L<=R){mid=(L+R)>>1; if(b[mid]<x) res=mid,L=mid+1; else R=mid-1;} if(b[res]>ans) ans=b[res];}for(int i=K[fa[r]].l;i<=r;i++) if(a[i]<x&&a[i]>ans) ans=a[i];
}
void work5(int l,int r,int x)
{ans=inf; if(fa[l]==fa[r]||fa[l]+1==fa[r]){for(int i=l;i<=r;i++) if(a[i]>x&&a[i]<ans) ans=a[i]; return ;}for(int i=l;i<=K[fa[l]].r;i++) if(a[i]>x&&a[i]<ans) ans=a[i];for(int k=fa[l]+1;k<fa[r];k++){int L=K[k].l,R=K[k].r,res,mid;if(b[R]<=x) continue; while(L<=R){mid=(L+R)>>1; if(b[mid]>x) res=mid,R=mid-1; else L=mid+1;} if(b[res]<ans) ans=b[res];}for(int i=K[fa[r]].l;i<=r;i++) if(a[i]>x&&a[i]<ans) ans=a[i];
}
int main()
{
//    freopen("ask.in","r",stdin);
//    freopen("ask.out","w",stdout);scanf("%d%d",&n,&T); sqr=sqrt(n);for(int i=1;i<=n;i++)fa[i]=(i-1)/sqr+1,scanf("%d",&a[i]),b[i]=a[i];for(int i=1;i<=n;i+=sqr)K[++m].l=i,K[m].r=i+sqr-1; K[m].r=n;for(int i=1;i<=m;i++) sort(b+K[i].l,b+K[i].r+1);int op,l,r,x;while(T--){scanf("%d%d%d",&op,&l,&r);if(op==3){a[l]=r; int k=fa[l];for(int i=K[k].l;i<=K[k].r;i++) b[i]=a[i];sort(b+K[k].l,b+K[k].r+1); continue;}scanf("%d",&x); if(op==2) {printf("%d\n",work2(l,r,x));continue;}if(op==1) work1(l,r,x),ans++; else if(op==4) work4(l,r,x);else work5(l,r,x); printf("%d\n",ans);}return 0;
}