#include <fstream>

using namespace std;
ifstream f("sequencequery.in");
ofstream g("sequencequery.out");
int n,m,a[100001],s;
long long smax;
void citire()
{
    f>>n>>m;
    for (int i=1;i<=n;i++)
        f>>a[i];
}
int main()
{
    int i,u,p,j;
    citire();
    for (i=1;i<=m;i++)
    {
        f>>p>>u;
        smax=-1000000000000;
        s=0;
        for (j=p;j<=u;j++)
        {
            s+=a[j];
            if (s>smax) smax=s;
            if (s<0) s=0;
        }
        g<<smax<<'\n';
    }
    return 0;
}