#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 998244353
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

template<typename Monoid>
struct SegmentTree{
    using F=function<Monoid(Monoid,Monoid)>;

    // private:
    int sz;
    vector<Monoid> seg;

    Monoid query(int a,int b,int k,int l,int r){
        if(a<=l and r<=b)   return seg[k];
        if(b<=l or r<=a)    return M0;
        Monoid L=query(a,b,2*k,l,(l+r)/2);
        Monoid R=query(a,b,2*k+1,(l+r)/2,r);
        return f(L,R);
    }
    template<typename C>
    int find_first(int a,const C &check,Monoid &acc,int k,int l,int r){
        if(k>=sz){
            acc=f(acc,seg[k]);
            if(check(acc))  return -1;
            else            return k-sz;
        }
        int m=(l+r)/2;
        if(m<=a) return find_first(a,check,acc,2*k+1,m,r);
        if(a<=l and check(f(acc,seg[k]))){
            acc=f(acc,seg[k]);
            return -1;
        }
        int x=find_first(a,check,acc,2*k+0,l,m);
        if(x>=0) return x;
        return find_first(a,check,acc,2*k+1,m,r);
    }
    template<typename C>
    int find_last(int b,const C &check,Monoid &acc,int k,int l,int r){
        if(k>=sz){
            acc=f(acc,seg[k]);
            if(check(acc))  return -1;
            else            return k-sz+1;//ここはfalse, +1した位置はtrue
        }
        int m=(l+r)/2;
        if(b<=m) return find_last(b,check,acc,2*k,l,m);
        if(r<=b and check(f(acc,seg[k]))){
            acc=f(acc,seg[k]);
            return -1;
        }
        int x=find_last(b,check,acc,2*k+1,m,r);
        if(x>=0) return x;
        return find_last(b,check,acc,2*k,l,m);
    }

    public:

    F f;
    Monoid M0;// モノイドの元
    SegmentTree(int n,F f,Monoid M0):f(f),M0(M0){
        sz=1;
        while(sz<n)sz<<=1;
        seg.assign(2*sz,M0);
    }
    void set(int k,Monoid x){
        seg[k+sz]=x;
    }
    void build(){
        for(int k=sz-1;k>0;k--) seg[k]=f(seg[2*k],seg[2*k+1]);
    }
    void update(int k,Monoid x){
        k+=sz;
        seg[k]=x;
        k>>=1;
        for(;k;k>>=1) seg[k]=f(seg[2*k],seg[2*k+1]);
    }
    Monoid query(int a,int b){
        return query(a,b,1,0,sz);
    }

    // http://codeforces.com/contest/914/submission/107505449
    // max x, check(query(a, x)) = true 
    template<typename C>
    int find_first(int a,const C &check){
        Monoid val=M0;
        return find_first(a,check,val,1,0,sz);
    }
    // http://codeforces.com/contest/914/submission/107505582
    // min x, check(query(x, b)) = true
    template<typename C>
    int find_last(int b,C &check){
        Monoid val=M0;
        return find_last(b,check,val,1,0,sz);
    }
};

template<typename T>
struct sums{
    T sum_all,sum_l,sum_r,sum_max;
    sums():sum_all(0),sum_l(0),sum_r(0),sum_max(0){}
    sums(T sum_all,T sum_l,T sum_r,T sum_max):sum_all(sum_all),sum_l(sum_l),sum_r(sum_r),sum_max(sum_max){}
};

template<typename T>
sums<T> f(sums<T> a,sums<T> b){
    sums<T> c;
    c.sum_all=a.sum_all+b.sum_all;
    c.sum_l=max(a.sum_l,a.sum_all+b.sum_l);
    c.sum_r=max(b.sum_r,b.sum_all+a.sum_r);
    c.sum_max=max({a.sum_max,b.sum_max,a.sum_r+b.sum_l});
    return c;
}

signed main(){
    int n,q;cin>>n>>q;
    
    using S=sums<ll>;
    
    SegmentTree<S> seg(n,f<ll>,S(0,0,0,0));
    rep(i,n){
        ll a;cin>>a;
        seg.set(i,sums(a,a,a,a));
    }
    seg.build();
    // rep(k,2*seg.sz) cout<<k<<" ! "<<seg.seg[k].sum_all<<" "<<seg.seg[k].sum_l<<" "<<seg.seg[k].sum_r<<" "<<seg.seg[k].sum_max<<endl;

    while(q--){
        string t;cin>>t;
        if(t=="set"){
            int idx;ll x;cin>>idx>>x;idx--;
            seg.update(idx,S(x,x,x,x));
        }else{
            int a,b,c,d;cin>>a>>b>>c>>d;a--,c--;
            if(c<=a) c=a+1;
            if(d<=b) b=d-1;
            if(b<c){
                auto mid=seg.query(b,c);
                auto l=seg.query(a,b);
                auto r=seg.query(c,d);
                cout<<(l.sum_r+mid.sum_all+r.sum_l)<<"\n";
            }else{
                auto mid=seg.query(c,b);
                auto l=seg.query(a,c);
                auto r=seg.query(b,d);

                ll res=-LINF;
                chmax(res,mid.sum_max);
                chmax(res,l.sum_r+mid.sum_l);
                chmax(res,mid.sum_r+r.sum_l);
                chmax(res,l.sum_r+mid.sum_all+mid.sum_l); 
                cout<<res<<"\n";
            }
        }
    }
    return 0;
}