#include <bits/stdc++.h>

using namespace std;
using i64 = int_fast64_t;
using db = long double;
using pii = pair<int, int>;
using pli = pair<int_fast64_t, int>;
using pdi = pair<double, int>;
template <class T> using mat = vector<vector<T>>;
template <class T> using minheap = priority_queue<T, vector<T>, greater<T>>;

#define each(i,v) for (auto i = begin(v); i != end(v); ++i)
#define reach(i,v) for (auto i = rbegin(v); i != rend(v); ++i)
#define urep(i,s,t) for (int i = (s); i <= (t); ++i)
#define drep(i,s,t) for (int i = (s); i >= (t); --i)
#define rep(i,n) urep(i, 0, (n)-1)
#define rep1(i,n) urep(i, 1, (n))
#define rrep(i,n) drep(i, (n)-1, 0)
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define fir first
#define sec second
#define front fro
#define back bac
#define vct vector
#define u_map unordered_map
#define u_set unordered_set
#define l_bnd lower_bound
#define u_bnd upper_bound
#define rsz resize
#define ers erase
#define emp emplace
#define emf emplace_front
#define emb emplace_back
#define pof pop_front
#define pob pop_back
#define mkp make_pair
#define mkt make_tuple
#define popcnt __builtin_popcount

struct setupper {
    setupper(uint_fast8_t prec) {
        ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
        std::cout.tie(nullptr);
        std::cout << fixed << setprecision(prec);
#ifdef Local
        auto print_atexit = []() { std::cerr << "Exec time : " << clock() / (double)CLOCKS_PER_SEC * 1000.0 << "ms\n"; };
        atexit((void(*)())print_atexit);
#endif
    }
} setuppre_obj(10);

namespace std {
    template <class T> void hash_combine(size_t &seed, T const &key) {
        seed ^= hash<T>()(key) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
    }
    template <class T, class U> struct hash<pair<T,U>> {
        size_t operator()(pair<T,U> const &pr) const
        {
            size_t seed = 0;
            hash_combine(seed,pr.first);
            hash_combine(seed,pr.second);
            return seed;
        }
    };
    template <class Tup, size_t index = tuple_size<Tup>::value - 1> struct hashval_calc {
        static void apply(size_t& seed, Tup const& tup) {
            hashval_calc<Tup, index - 1>::apply(seed, tup);
            hash_combine(seed,get<index>(tup));
        }
    };
    template <class Tup> struct hashval_calc<Tup,0> {
        static void apply(size_t& seed, Tup const& tup) {
            hash_combine(seed,get<0>(tup));
        }
    };
    template <class ...T> struct hash<tuple<T...>> {
        size_t operator()(tuple<T...> const& tup) const
        {
            size_t seed = 0;
            hashval_calc<tuple<T...>>::apply(seed,tup);
            return seed;
        }
    };
}

template <class T, class U> ostream& operator << (ostream& s, pair<T,U> p) { return s << p.fir << " " << p.sec; }
template <class T> ostream& operator << (ostream& s, vct<T> v) { each(i,v) { if(i != begin(v)) s << " "; s << *i; } return s; }
#define dump(...) cerr << " [ " << __LINE__ << " : " << __FUNCTION__ << " ] " << #__VA_ARGS__ << " : ";\
dump_func(__VA_ARGS__)
template <class T> void dump_func(T x) { cerr << x << '\n'; }
template <class T,class ...Rest> void dump_func(T x, Rest ... rest) { cerr << x << ","; dump_func(rest...); }
template <class T = int> T read() { T x; return cin >> x, x; }
template <class T> void write(T x) { cout << x << '\n'; }
template <class T, class ...Rest> void write(T x, Rest ... rest) { cout << x << ' '; write(rest...); }
void writeln() {}
template <class T, class ...Rest> void writeln(T x, Rest ... rest) { cout << x << '\n'; writeln(rest...); }
#define esc(...) writeln(__VA_ARGS__), exit(0)
const auto add = [](auto &x, auto y) { x += y; };
const auto mul = [](auto &x, auto y) { x *= y; };
const auto lam_min = [](auto x, auto y) { return min(x, y); };
const auto lam_max = [](auto x, auto y) { return max(x, y); };
const auto chmax = [](auto &m, auto x) { if(m < x){ m = x; return true; } return false; };
const auto chmin = [](auto &m, auto x) { if(m > x){ m = x; return true; } return false; };
bool bit(i64 n, uint8_t e) { return (n >> e) & 1; }
i64 mask(i64 n, uint8_t e) { return n & ((1 << e) - 1); }
int ilog(uint64_t x, uint64_t b = 2) { return x ? 1 + ilog(x / b,b) : -1; }
template <class F> i64 binsr(i64 ok, i64 ng, const F &fn) {
    while (abs(ok - ng) > 1) {
        i64 mid = (ok + ng) / 2;
        (fn(mid) ? ok : ng) = mid;
    }
    return ok;
}
template <class A, size_t N, class T> void init(A (&array)[N], const T &val) { fill((T*)array,(T*)(array + N),val); }
template <class T> T cmprs(T &v) {
    T tmp = v, ret = v;
    sort(all(tmp));
    tmp.erase(unique(all(tmp)), end(tmp));
    each(i,ret) *i = l_bnd(all(tmp),*i) - begin(tmp);
    return ret;
}

template <class T> constexpr T inf = numeric_limits<T>::max() / 2 - 1;
constexpr int dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
constexpr int dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr long double gold = 1.618033988;
constexpr long double eps = 1e-15;
constexpr uint_fast64_t mod = 1e9 + 7;


template <class Monoid> struct Segtree {
    typedef function<Monoid(const Monoid&, const Monoid&)> opr_t;
    typedef function<void(Monoid&, const Monoid&)> update_opr_t;
    const opr_t opr;
    const update_opr_t update_opr;
    const Monoid idel;
    vector<Monoid> data;
    const int n;
    int range;

    Segtree(int n_, Monoid idel_ = Monoid(), const opr_t &opr_ = plus<Monoid>(), const update_opr_t &update_opr_ = [](Monoid &x,Monoid y){x = y;}) : n(n_),opr(opr_),update_opr(update_opr_),idel(idel_)
    {
        range = 1;
        while(n >= range) range <<= 1;
        data.assign(range << 1,idel);
    }

    void copy(const vector<Monoid> &v) {
        for(int i = 0; i < v.size(); ++i) data[i + range] = v[i];
        for(int i = range - 1; i; i--) data[i] = opr(data[i * 2],data[i * 2 + 1]);
    }

    void update(int idx, Monoid val) {
        update_opr(data[idx += range],val);
        while(idx >>= 1) data[idx] = opr(data[idx * 2],data[idx * 2 + 1]);
    }

    Monoid query(int a, int b, bool is_first = true) {
        if(a >= b) return idel;
        if(is_first) {
            a += range;
            b += range;
        }
        Monoid left = a & 1 ? data[a++] : idel;
        Monoid right = b & 1 ? data[--b] : idel;
        return opr(opr(left,query(a >> 1,b >> 1,false)),right);
    }

    int bound(int i, function<bool(Monoid,int)> judge) {
        int w = 1,rig = i,j = range << 1;
        i += range;
        while(i < j) {
            if(i & 1) {
                rig += w;
                if(!judge(data[i],w)) break;
                i++;
            }
            i >>= 1,j >>= 1,w <<= 1;
        }
        if(i == j) return n;
        while(w > 1) {
            if(judge(data[i <<= 1],w >>= 1)) ++i;
            else rig -= w;
        }
        return min(n,rig - 1);
    }
};

struct node {
    i64 lf,rg,cn,al,lf2,rg2;
    node() : lf(0),rg(0),lf2(-inf<i64>),rg2(-inf<i64>),cn(-inf<i64>),al(0) {}
    node(int v) {
        lf2=rg2=cn=al=v;
        lf=max(al,0L);
        rg=max(0L,al);
    }
};

node calc(const node &a,const node &b) {
    if(a.lf2==-inf<i64>) return b;
    if(b.lf2==-inf<i64>) return a;
    node ret;
    ret.al=a.al+b.al;
    ret.lf=max(a.lf,a.al+b.lf);
    ret.lf2=max(a.lf2,a.lf2!=inf<i64>?a.al+b.lf:b.lf2);
    ret.rg=max(b.rg,b.al+a.rg);
    ret.rg2=max(b.rg2,b.rg2!=inf<i64>?b.al+a.rg:a.rg2);
    ret.cn=max({a.cn,b.cn,a.rg+b.lf2,a.rg2+b.lf});
    return ret;
}

int n,qry;

int main() {
    cin>>n>>qry;
    Segtree<node> sg(n,node(),calc);
    for(int i=0; i<n; ++i) {
        sg.update(i,node(read()));
    }
    while(qry--) {
        string kind;
        cin>>kind;
        if(kind=="set") {
            int i,x;
            cin>>i>>x;
            sg.update(--i,node(x));
        } else {
            int a,b,c,d;
            cin>>a>>b>>c>>d;
            --a,--b,--c,--d;
            if(b<c) {
                node lt=sg.query(a,b+1);
                node rt=sg.query(c,d+1);
                node mt=sg.query(b+1,c);
                writeln(mt.al+lt.rg2+rt.lf2);
            } else {
                c=max(a,c);
                b=min(d,b);
                i64 ans=-inf<i64>;
                chmax(ans,sg.query(a,c).rg+sg.query(c,d+1).lf2);
                chmax(ans,sg.query(b+1,d+1).lf+sg.query(a,b+1).rg2);
                chmax(ans,sg.query(c,b).cn);
                writeln(ans);
            }
        }
    }
}