#include <fstream>
#include <climits>
#define sz 100000
using namespace std;
ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");

int n,m;

struct NNodNN
{
    int secv;
    int pref;
    int suf;
    int sum;
};

NNodNN a[sz*4];


NNodNN calc(NNodNN a,NNodNN b)
{
    NNodNN 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 nod,int st,int dr)
{
    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 mid = (st+dr)/2;
    build(nod*2,st,mid);
    build(nod*2+1,mid+1,dr);
    a[nod] = calc(a[nod*2],a[nod*2+1]);
}
NNodNN query(int nod,int st,int dr,int x,int y)
{
    if(x<=st && dr<=y)
        return a[nod];
    int mid = (st+dr)/2;
    if( y<= mid)
        return query(nod*2,st,mid,x,y);
    else if( x> mid)
        return query(nod*2+1,mid+1,dr,x,y);
    else
    {
        NNodNN n1 = query(nod*2,st,mid,x,y);
        NNodNN n2 = query(nod*2+1,mid+1,dr,x,y);
        return calc(n1,n2);
    }
}

int main()
{
    fin>>n>>m;
    build(1,1,n);
    for(int i=1;i<=m;i++)
    {
        int x,y;
        fin>>x>>y;
        fout<<query(1,1,n,x,y).secv<<'\n';
    }

}