#include <bits/stdc++.h>
#define MAX 100005

using namespace std;

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

int v[MAX];
struct str
{
    long long sum;
    long long inc;
    long long fin;
    long long best;
}aint[4*MAX];

void build(int nod,int st,int dr)
{
    if(st==dr)
        aint[nod]={v[st],v[st],v[st],v[st]};
    else
    {
        int mij=(st+dr)/2;
        build(2*nod,st,mij);
        build(2*nod+1,mij+1,dr);
        aint[nod].sum=aint[2*nod].sum+aint[2*nod+1].sum;
        aint[nod].inc=max(aint[2*nod].inc,aint[2*nod].sum+aint[2*nod+1].inc);
        aint[nod].fin=max(aint[2*nod+1].fin,aint[2*nod].fin+aint[2*nod+1].sum);
        aint[nod].best=max(max(aint[2*nod].best,aint[2*nod+1].best),aint[2*nod].fin+aint[2*nod+1].inc);
    }
}

long long rasp;
long long sircrt;

void query(int nod,int st,int dr,int a,int b)
{
    if(a<=st && dr<=b)
    {
        rasp=max(rasp,aint[nod].best);
        rasp=max(rasp,sircrt+aint[nod].inc);
        sircrt=max(sircrt+aint[nod].sum,aint[nod].fin);
    }
    else
    {
        int mij=(st+dr)/2;
        if(a<=mij)
            query(2*nod,st,mij,a,b);
        if(b>mij)
            query(2*nod+1,mij+1,dr,a,b);
    }
}

int main()
{
    int n,m;
    fin>>n>>m;
    int i;
    for(i=1;i<=n;++i)
        fin>>v[i];
    build(1,1,n);
    while(m--)
    {
        int x,y;
        fin>>x>>y;
        rasp=-1e18;
        sircrt=-1e18;
        query(1,1,n,x,y);
        fout<<rasp<<'\n';
    }
    return 0;
}