#include <iostream>
#include <fstream>

using namespace std;

ofstream g("sequencequery.out");
ifstream f("sequencequery.in");

int main()
{
    long v[100005];
    long long int n, m, i, j, S, a, b, bestSum=-1000000000000, sum=0;
    f>>n>>m;
    for (i=0;i<n;i++)
        f>>v[i];
    for (i=0;i<m;i++)
    {
        sum=0;
        bestSum=-1000000000000;
        f>>a>>b;
        for (j=a-1;j<=b-1;j++)
        {
            if (sum<0)
                sum=v[j];
            else
                sum=sum+v[j];
            if (bestSum<sum)
                bestSum=sum;
        }
        g<<bestSum<<'\n';
    }
    return 0;
}