#include <bits/stdc++.h>

using namespace std;

ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");
struct Nod
{
    long long secv, pref, suf, sum;
} a[400002];
int n, t, i, x, y;


Nod Calc(Nod a, Nod b)
{
    Nod c;
    c.sum = a.sum + b.sum;
    c.pref = max(a.pref, a.sum + b.pref);
    c.suf = max(b.suf,   b.sum + a.suf);
    c.secv = max(max(a.secv, b.secv), a.suf + b.pref);
    return c;
}


void build(int st, int dr, int nod)
{
    if(st == dr)
    {
        fin >> a[nod].sum;
        a[nod].pref = a[nod].sum;
        a[nod].suf  = a[nod].sum;
        a[nod].secv = a[nod].sum;
        return;
    }

    int mij = st + (dr - st) / 2;
    build(st, mij, nod * 2);
    build(mij + 1, dr, nod * 2 + 1);
    a[nod] = Calc(a[nod * 2], a[nod * 2 + 1]);
}

Nod interogare(int st, int dr, int nod)
{
    if(x <= st && dr <= y) return a[nod];
    int mij = st + (dr - st) / 2;
    if(y <= mij)
        return interogare(st, mij, nod * 2);
    else
        if(x > mij)
            return interogare(mij + 1,  dr, nod * 2 + 1);
    else
        return Calc(interogare(st, mij, nod * 2), interogare(mij + 1,  dr, nod * 2 + 1));
}

int main()
{
    fin >> n >> t;
    build(1, n, 1);
    while(t--)
    {
        fin >> x >> y;
        fout << interogare(1, n, 1).secv << "\n";
    }

    return 0;
}