#include<stdio.h>
#include<algorithm>
#include<iostream>
using namespace std;

int v[100100],N,M,l,r;

long long query(int l, int r)
{
    long long s=0, ma=-200000;

    for(int i=l;i<=r;++i)
    {
        if(v[i]>ma)
            ma=v[i];
    }

    if(ma<0)
    {
        return ma;
    }

    for(int i=l;i<=r;++i)
    {
        s+=v[i];
        if(s<0)
        {
            s = 0;
        }
        ma = max(ma,s);

    }

    return ma;
}

int main()
{
    freopen("sequencequery.in","r",stdin);
    freopen("sequencequery.out","w",stdout);
    scanf("%d%d",&N,&M);
    for(int i=1;i<=N;++i)
    {
        scanf("%d",&v[i]);
    }

    for(int i=1;i<=M;++i)
    {
        scanf("%d%d",&l,&r);
        printf("%lld\n",query(l,r));
    }
    return 0;
}