#include <fstream>

using namespace std;
ifstream cin("sequencequery.in");
ofstream cout("sequencequery.out");
int v[100005];
int main()
{
    int n,m,i,a,b,s,ma,j;
    cin>>n>>m;
    for(i=1;i<=n;i++)
        cin>>v[i];
    for(i=1;i<=m;i++)
    {
        cin>>a>>b;
        s=0;
        ma=-100000;
        for(j=a;j<=b;j++)
        {
            if(s<0)
               s=v[j];
            else
                s+=v[j];
            ma=max(ma,s);
        }
        cout<<ma<<'\n';
    }
    return 0;
}