using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

partial class Solver
{
    static public bool UpdateMax<T>(ref T x, T newValue) where T : IComparable<T>
    {
        if (x.CompareTo(newValue) < 0) { x = newValue; return true; }
        return false;
    }

    public void Run()
    {
        var N = ni();
        var Q = ni();
        var a = ni(N);

        var tree = new SegmentTreeImpl();
        tree.Build(a.Select(x => new NodeValue { Left = x, Middle = x, Right = x, Sum = x }).ToArray());

        for (int t = 0; t < Q; t++)
        {
            var type = ns();
            if (type == "set")
            {
                var i = ni() - 1;
                var x = ni();
                tree.Update(i, new NodeValue { Left = x, Middle = x, Right = x, Sum = x });
            }
            else
            {
                var l1 = ni() - 1;
                var l2 = ni() - 1;
                var r1 = ni() - 1;
                var r2 = ni() - 1;
                if (r1 < l1) r1 = l1;
                if (r2 < l2) l2 = r1;

                long ans = 0;

                if (l2 < r1) // [l1 .. l2] < [r1 .. r2]
                {
                    var left = tree.Query(l1, l2 + 1);
                    var right = tree.Query(r1, r2 + 1);
                    var middle = (l2 + 1 < r1) ? tree.Query(l2 + 1, r1) : default(NodeValue);

                    ans = left.Right + middle.Sum + right.Left;
                }
                else
                {
                    var m1 = r1;
                    var m2 = l2;

                    var left = l1 < m1 ? tree.Query(l1, m1) : default(NodeValue);
                    var middle = (m1 < m2 + 1) ? tree.Query(m1, m2 + 1) : default(NodeValue);
                    var right = (m2 + 1 < r2 + 1) ? tree.Query(m2 + 1, r2 + 1) : default(NodeValue);

                    ans = long.MinValue;
                    UpdateMax(ref ans, middle.MaxValue);
                    UpdateMax(ref ans, left.Right + middle.Sum + right.Left);
                    UpdateMax(ref ans, left.Right + middle.Left);
                    UpdateMax(ref ans, middle.Right + right.Left);
                }

                cout.WriteLine(ans);
            }
        }
    }

}

public struct NodeValue
{
    public long Left { get; set; }
    public long Middle { get; set; }
    public long Right { get; set; }
    public long Sum { get; set; }
    public long MaxValue => new[] { Left, Middle, Right }.Max();
}

public class SegmentTreeImpl : SegmentTree<NodeValue>
{
    protected override NodeValue Merge(NodeValue x, NodeValue y)
    {
        return new NodeValue
        {
            Sum = x.Sum + y.Sum,
            Left = Math.Max(x.Left, x.Sum + y.Left),
            Middle = Math.Max(Math.Max(x.Middle, y.Middle), x.Right + y.Left),
            Right = Math.Max(y.Right, y.Sum + x.Right),
        };
    }
}

public abstract class SegmentTree<TNodeValue> where TNodeValue : struct
{
    protected int N { get; private set; }
    protected TNodeValue?[] node;
    protected static int Left(int p) { return p * 2 + 1; }
    protected static int Right(int p) { return p * 2 + 2; }

    public SegmentTree() { }

    public void Build(IList<TNodeValue> array)
    {
        Build(array.Count, i => array[i]);
    }

    virtual public void Build(int _n, Func<int, TNodeValue> create)
    {
        N = 1;
        while (N < _n) N *= 2;
        node = new TNodeValue?[2 * N];

        for (int i = 0; i < _n; i++) node[i + N - 1] = create(i);
        for (int i = N - 2; i >= 0; i--) node[i] = Merge(node[Left(i)], node[Right(i)]);
    }

    protected TNodeValue? Merge(TNodeValue? left, TNodeValue? right)
    {
        if (left != null && right != null) return Merge(left.Value, right.Value);
        if (left == null) return right;
        if (right == null) return left;
        return null;
    }

    protected abstract TNodeValue Merge(TNodeValue left, TNodeValue right);

    public void Update(int index, TNodeValue val)
    {
        int p = index + N - 1;
        node[p] = val;
        while (p > 0)
        {
            p = (p - 1) / 2;
            node[p] = Merge(node[Left(p)], node[Right(p)]);
        }
    }

    protected virtual TNodeValue? Query(int begin, int end, int k, int l, int r)
    {
        if (r <= begin || end <= l) return null;
        if (begin <= l && r <= end) return node[k];
        int mid = (l + r) / 2;
        return Merge(
            Query(begin, end, Left(k), l, mid),
            Query(begin, end, Right(k), mid, r)
        );
    }

    public TNodeValue Query(int begin, int end)
    {
        return Query(begin, end, 0, 0, N).Value;
    }
};

// PREWRITEN CODE BEGINS FROM HERE
partial class Solver : Scanner
{
    public static void Main(string[] args)
    {
        new Solver(Console.In, Console.Out).Run();
    }

    TextReader cin;
    TextWriter cout;

    public Solver(TextReader reader, TextWriter writer)
        : base(reader)
    {
        this.cin = reader;
        this.cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer)
    {
    }

    public int ni() { return NextInt(); }
    public int[] ni(int n) { return NextIntArray(n); }
    public long nl() { return NextLong(); }
    public long[] nl(int n) { return NextLongArray(n); }
    public double nd() { return NextDouble(); }
    public string ns() { return Next(); }
    public string[] ns(int n) { return NextArray(n); }
}

public class Scanner
{
    private TextReader Reader;
    private Queue<String> TokenQueue = new Queue<string>();
    private CultureInfo ci = CultureInfo.InvariantCulture;

    public Scanner()
        : this(Console.In)
    {
    }

    public Scanner(TextReader reader)
    {
        this.Reader = reader;
    }

    public int NextInt() { return Int32.Parse(Next(), ci); }
    public long NextLong() { return Int64.Parse(Next(), ci); }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size)
    {
        var array = new string[size];
        for (int i = 0; i < size; i++) array[i] = Next();
        return array;
    }
    public int[] NextIntArray(int size)
    {
        var array = new int[size];
        for (int i = 0; i < size; i++) array[i] = NextInt();
        return array;
    }

    public long[] NextLongArray(int size)
    {
        var array = new long[size];
        for (int i = 0; i < size; i++) array[i] = NextLong();
        return array;
    }

    public String Next()
    {
        if (TokenQueue.Count == 0)
        {
            if (!StockTokens()) throw new InvalidOperationException();
        }
        return TokenQueue.Dequeue();
    }

    public bool HasNext()
    {
        if (TokenQueue.Count > 0)
            return true;
        return StockTokens();
    }

    private bool StockTokens()
    {
        while (true)
        {
            var line = Reader.ReadLine();
            if (line == null) return false;
            var tokens = line.Trim().Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
            if (tokens.Length == 0) continue;
            foreach (var token in tokens)
                TokenQueue.Enqueue(token);
            return true;
        }
    }
}