#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#define INF 2140000000
#define MaxT 265000
#define MaxN 100001
#define MAX 131072
using namespace std;

FILE *IN,*OUT;
struct _Tree
{
	long long Sum,Left,Right,Max;
}T[MaxT];
int N,M,pos=0,v[MaxN],Start,End,Type,Ans,P,Val,out=0,sign,Previous;
char f[MAX],Out[MAX],str[20];
inline void Write_Ch(char ch)
{
	Out[out++]=ch;
	if(out==MAX)
		fwrite(Out,MAX,1,OUT),out=0;
}
inline void Write_Int(long long nr)
{
	int x=0;
	if(nr<0)Write_Ch('-'),nr=-nr;
	do
	{
		str[x++]=nr%10+'0';
		nr/=10;
	}
	while(nr);
	while(x>0)
		Write_Ch(str[--x]);
}
inline long long max2(long long a,long long b)
{
	if (a>b) return a;
	else return b;
}
inline void Read(long long &nr)
{
	sign=0;
	nr=0;
	while(f[pos]<'0'||f[pos]>'9')
	{
		if(f[pos]=='-')sign=1;
		pos++;
		if(pos==MAX)
			fread(f,MAX,1,IN),pos=0;
	}
	while(f[pos]>='0'&&f[pos]<='9')
	{
		nr=10*nr+f[pos++]-'0';
		if(pos==MAX)
			fread(f,MAX,1,IN),pos=0;
	}
	if(sign)nr=-nr;
}
void DFS(int node,int start,int end)
{
	if(start==end)
	{
		T[node].Left=T[node].Right=T[node].Max=T[node].Sum=v[start];
		return;
	}
	DFS(node*2,start,(start+end)>>1);
	DFS(node*2+1,((start+end)>>1)+1,end);
	T[node].Sum=T[node*2].Sum+T[node*2+1].Sum;
	T[node].Left=max2(T[2*node].Sum+T[2*node+1].Left,T[2*node].Left);
	T[node].Right=max2(T[2*node+1].Sum+T[2*node].Right,T[2*node+1].Right);
	T[node].Max=max2(max2(T[2*node].Max,T[2*node+1].Max),T[2*node].Right+T[2*node+1].Left);
}
/*void Update(int node,int start,int end)
{
	if(start==end)
	{
		T[node]=Val;
		return;
	}
	int mid=(start+end)>>1;
	if(P>mid)
		Update(node*2+1,mid+1,end);
	else Update(node*2,start,mid);
	T[node]=max2(T[2*node],T[2*node+1]);
}*/
void Query(int node,int start,int end)
{
	if(start>=Start&&end<=End)
	{
		Ans=max2(Ans,max2(Previous+T[node].Left,T[node].Max));
		Previous=max(Previous+T[node].Sum,T[node].Right);
	}
	else
	{
		int mid=(start+end)>>1;
		if (Start<=mid)
			Query(node*2,start,mid);
		if(End>mid) Query(node*2+1,mid+1,end);
	}
}
int main()
{
    IN=fopen("sequencequery.in","r");
	OUT=fopen("sequencequery.out","w");
	fread(f,1,MAX,IN);
	Read(N);
	Read(M);
	for(int i=1;i<=N;i++)
		Read(v[i]);
	DFS(1,1,N);
	for(int i=1;i<=M;i++)
	{
		Previous=0;
		Ans=-INF;
		Read(Start),Read(End);
		Query(1,1,N);
		Write_Int(Ans);
		Write_Ch('\n');
	}
	if(out>0)fwrite(Out,1,out,OUT);
    return 0;
}