//minamoto

 #include<iostream>

 #include<cstdio>

 #include<set>

 #define IT set<node>::iterator

 using std::set;

 #define getc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)

 char buf[<<],*p1=buf,*p2=buf;

 template<class T>inline bool cmax(T&a,const T&b){return a<b?a=b,:;}

 int read(){

     #define num ch-'0'

     char ch;bool flag=;int res;

     while(!isdigit(ch=getc()))

     (ch=='-')&&(flag=true);

     for(res=num;isdigit(ch=getc());res=res*+num);

     (flag)&&(res=-res);

     #undef num

     return res;

 }

 char sr[<<],z[];int C=-,Z;

 inline void Ot(){fwrite(sr,,C+,stdout),C=-;}

 void print(int x){

     if(C><<)Ot();if(x<)sr[++C]=,x=-x;

     while(z[++Z]=x%+,x/=);

     while(sr[++C]=z[Z],--Z);sr[++C]='\n';

 }

 const int N=2e5+;

 struct node{

     int l,r;mutable bool v;

     node(int L,int R=-,bool V=):l(L),r(R),v(V){}

     inline bool operator <(const node &b)const

     {return l<b.l;}

 };set<node> s;

 IT split(int pos){

     IT it=s.lower_bound(node(pos));

     if(it!=s.end()&&it->l==pos) return it;

     --it;int l=it->l,r=it->r;bool v=it->v;

     s.erase(it),s.insert(node(l,pos-,v));

     return s.insert(node(pos,r,v)).first;

 }

 void assign(int l,int r){

     IT itr=split(r+),itl=split(l);

     s.erase(itl,itr),s.insert(node(l,r,));

 }

 int count(int l,int r){

     IT itr=split(r+),itl=split(l);int res=;

     for(IT it=itl;it!=itr;++it) res+=it->v?it->r-it->l+:;

     s.erase(itl,itr),s.insert(node(l,r,));

     return res;

 }

 void fi(int l,int r,int cnt){

     IT itr=split(r+),itl=split(l);

     for(;itl!=itr;++itl)

     if(itl->v==){

         if(cnt<=itl->r-itl->l+){

             if(cnt==itl->r-itl->l+) itl->v=;

             else{

                 int ql=itl->l,qr=itl->r;

                 s.erase(itl),s.insert(node(ql,ql+cnt-,)),s.insert(node(ql+cnt,qr,));

             }

             return;

         }else itl->v=,cnt-=itl->r-itl->l+;

     }

 }

 void recov(int l,int r,int ql,int qr){

     int res=count(l,r);

     if(res) fi(ql,qr,res);

 }

 int sum(int l,int r){

     IT itr=split(r+),itl=split(l);int res=,tmp=;

     for(;itl!=itr;++itl)

     itl->v==?(tmp+=itl->r-itl->l+):(cmax(res,tmp),tmp=);

     return std::max(res,tmp);

 }

 int main(){

 //    freopen("testdata.in","r",stdin);

     int n=read(),m=read();

     s.insert(node(,n,));

     while(m--){

         int op=read(),l=read(),r=read(),ql,qr;

         switch(op){

             case :assign(l,r);break;

             case :ql=read(),qr=read(),recov(l,r,ql,qr);break;

             case :print(sum(l,r));break;

         }

     }

     return Ot(),;

 }