#include<iostream>
#include<fstream>
using namespace std;
ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");
int v[100001];
int main()
{
    int n,k;
    fin>>n>>k;
    for (int i=1;i<=n;i++)
    {
        fin>>v[i];
    }
    int S;
    while (k!=0)
    {
        int st,sp;
        fin>>st>>sp;
        S=v[st];
        int maxim=S;
        for (int i=st+1;i<=sp;i++)
        {
            if (S+v[i]<=v[i])
                S=v[i];
            else
                S=S+v[i];
            if (S>maxim)
                maxim=S;
        }
        fout<<maxim<<"\n";
        k--;
    }
}