#include <bits/stdc++.h>


#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...)
#endif


template <typename Monoid, bool COMMUTATIVE = false>
class SegmentTree{
  using value_type = typename Monoid::value_type;
  
protected:
  const int depth, size, hsize;
  std::vector<value_type> data;

public:
  SegmentTree(int n):
    depth(n > 1 ? 32-__builtin_clz(n-1) + 1 : 1),
    size((1 << depth) - 1),
    hsize(size / 2 + 1),
    data(size + 1, Monoid::id())
  {}

  inline auto operator[](int i) const {return at(i);}
  inline auto at(int i) const {return data[hsize + i];}
  
  inline auto get(int x, int y) const { // [x,y)
    std::vector<int> memo;
    value_type ret = Monoid::id();
    
    int l = x + hsize, r = y + hsize;
    while(l < r){
      if(r & 1){
        if(COMMUTATIVE) ret = Monoid::op(ret, data[--r]);
        else memo.push_back(--r);
      }
      if(l & 1) ret = Monoid::op(ret, data[l++]);
      l >>= 1, r >>= 1;
    }

    if(not COMMUTATIVE){
      std::reverse(memo.begin(), memo.end());
      for(auto i : memo) ret = Monoid::op(ret, data[i]);
    }
    
    return ret;
  }

  inline void update(int i, const value_type &x){
    i += hsize;
    data[i] = x;
    while(i > 1) i >>= 1, data[i] = Monoid::op(data[i << 1 | 0], data[i << 1 | 1]);
  }

  template <typename T>
  inline void init_with_vector(const std::vector<T> &val){
    data.assign(size + 1, Monoid::id());
    for(int i = 0; i < (int)val.size(); ++i) data[hsize + i] = val[i];
    for(int i = hsize-1; i >= 1; --i) data[i] = Monoid::op(data[i << 1 | 0], data[i << 1 | 1]);
  }

  template <typename T>
  inline void init(const T &val){
    init_with_vector(std::vector<value_type>(hsize, val));
  }  

  auto debug(){
    return data;
  }
};




template <typename T>
struct MaxPartialSum{
  T sum, left_max, right_max, partial_max;
  static auto make(T x){return MaxPartialSum<T>({x, std::max<T>(x, 0), std::max<T>(x, 0), std::max<T>(x, 0)});}
};

template <typename T>
struct MaxPartialSumMonoid{
  using value_type = MaxPartialSum<T>;

  
  constexpr inline static value_type id(){
    return {0, 0, 0, 0};
  }
  
  constexpr inline static value_type op(const value_type &a, const value_type &b){
    return {
            a.sum + b.sum,
            std::max(a.left_max, a.sum + std::max(b.left_max, b.sum)),
            std::max(b.right_max, b.sum + std::max(a.right_max, a.sum)),
            std::max({a.partial_max, b.partial_max, a.right_max + b.left_max})
    };
  }
};

using Mon = MaxPartialSumMonoid<int64_t>;



template <typename T, typename U>
void chmax(T &a, const U &b){
  a = std::max(a, b);
}


int main(){
  int N,Q;
  while(std::cin >> N >> Q){
    SegmentTree<Mon, false> seg(N);

    std::vector<int64_t> a(N);

    for(int i = 0; i < N; ++i){
      std::cin >> a[i];
      seg.update(i, MaxPartialSum<int64_t>::make(a[i]));
    }

    for(int i = 0; i < Q; ++i){
      std::string com; std::cin >> com;

      if(com == "set"){
        int i, x; std::cin >> i >> x;
        --i;
        seg.update(i, MaxPartialSum<int64_t>::make(x));
        a[i] = x;
      }else{
        int l1, l2, r1, r2; std::cin >> l1 >> l2 >> r1 >> r2;
        --l1, --l2, --r1, --r2;

        r1 = std::max(l1,r1);
        l2 = std::min(l2,r2);

        //dump(a, std::make_pair(l1, l2), std::make_pair(r1, r2));
        
        int64_t ans = LLONG_MIN;

        auto f = [&](int L1, int L2, int R1, int R2){return seg.get(L1, L2).right_max + seg.get(L2, R1+1).sum + seg.get(R1+1, R2+1).left_max;};
        
        if(l2 <= r1){
          ans = f(l1, l2, r1, r2);
        }else{
          chmax(ans, f(l1, r1, r1, r2));
          chmax(ans, f(l1, l2, l2, r2));
          chmax(ans, seg.get(r1, l2+1).partial_max);
        }

        std::cout << ans << std::endl;
      }
    }

    std::cerr << std::endl;
  }


  return 0;
}