#include <cstdio>

using namespace std;
int n,m,i,v[100050],j,x,y,t,sc,scmax;
int main()
{
    freopen("sequencequery.in","r",stdin);
    freopen("sequencequery.out","w",stdout);

    scanf("%d%d",&n,&m);

    for(i=1; i<=n; i++)
        scanf("%d",&v[i]);

    for(i=1; i<=m; i++)
    {
        sc=0;
        scmax=-100000;
        scanf("%d%d",&x,&y);
        for(j=x; j<=y; j++)
        {
            sc+=v[j];
            if(sc<=v[j])
            {
                sc=v[j];
                t=j;
            }
            if(scmax<sc)
                scmax=sc;

        }
        printf("%d\n",scmax);
    }
    return 0;
}