#include <fstream>
using namespace std;
ifstream fin ("sequencequery.in");
ofstream fout("sequencequery.out");
int n,m,x,y,T,V[200002];
struct elem
{
	long long suma,p,s,ssm;
}A[800003];
elem U(elem x,elem y)
{
	elem R;
	R.suma=x.suma+y.suma;
	R.p=max(x.p,x.suma+y.p);
	R.s=max(y.s,y.suma+x.s);
	R.ssm=max(y.p+x.s,max(x.ssm,y.ssm));
	return R;
}
void build(int nod,int st,int dr)
{
	if(st==dr)
		A[nod]={V[st],V[st],V[st],V[st]};
	else
	{
		int mid=(st+dr)/2;
		build(2*nod,st,mid);
		build(2*nod+1,mid+1,dr);
		A[nod]=U(A[2*nod],A[2*nod+1]);
	}
}
elem Q(int nod,int st,int dr,int a,int b)
{
	if(a<=st&&dr<=b)
        return A[nod];
	else
	{
		int mid=(st+dr)/2;
		if(mid>=b)
			return Q(2*nod,st,mid,a,b);
		if(mid<a)
			return Q(2*nod+1,mid+1,dr,a,b);
		return U(Q(2*nod,st,mid,a,b),Q(2*nod+1,mid+1,dr,a,b));
	}
}
int main()
{

	fin>>n>>m;
	for(int i=1;i<=n;i++)
		fin>>V[i];
	build(1,1,n);
	for(int i=1;i<=m;i++)
	{
		fin>>x>>y;
        fout<<Q(1,1,n,x,y).ssm<<"\n";

    }
	return 0;
}