#include <fstream>
#include <vector>

using namespace std;

using int64 = long long;

struct Node
{
    int64 left, right;
    int64 best, total;
};

using Aint = vector<Node>;

const int64 kInf = (1LL << 50);
const Node kMinNode = (Node){-kInf, -kInf, -kInf, -kInf};

inline int LeftSon(int n) { return (n << 1); }
inline int RightSon(int n) { return (n << 1) + 1; }

Node Combine(const Node &lson, const Node &rson)
{
    Node father = kMinNode;
    father.left = max(lson.left, lson.total + rson.left);
    father.right = max(rson.right, rson.total + lson.right);
    father.total = lson.total + rson.total;

    father.best = max(lson.best, rson.best);
    father.best = max(father.best, lson.right + rson.left);
    return father;
}

void Update(Aint &aint, int ind, int l, int r, int pos, int val)
{
    if (l == r) {
        aint[ind] = (Node){val, val, val, val};
        return;
    }

    int mid = l + (r - l) / 2;
    if (pos <= mid) {
        Update(aint, LeftSon(ind), l, mid, pos, val);
    } else {
        Update(aint, RightSon(ind), mid + 1, r, pos, val);
    }
    aint[ind] = Combine(aint[LeftSon(ind)], aint[RightSon(ind)]);
}

Node Query(const Aint &aint, int ind, int l, int r, int x, int y)
{
    if (x <= l && r <= y) {
        return aint[ind];
    }

    int mid = l + (r - l) / 2;
    Node node_left = kMinNode;
    Node node_right = kMinNode;

    if (x <= mid) {
        node_left = Query(aint, LeftSon(ind), l, mid, x, y);
    }
    if (y > mid) {
        node_right = Query(aint, RightSon(ind), mid + 1, r, x, y);
    }
    return Combine(node_left, node_right);
}

int main()
{
    ifstream fin("sequencequery.in");
    ofstream fout("sequencequery.out");

    int n, m;
    fin >> n >> m;

    Aint aint(4 * n + 4, kMinNode);
    for (int i = 1; i <= n; ++i) {
        int x;
        fin >> x;
        Update(aint, 1, 1, n, i, x);
    }


    while (m--) {
        int x, y;
        fin >> x >> y;
        fout << Query(aint, 1, 1, n, x, y).best << "\n";
    }

    return 0;
}