#include <fstream>
#include <climits>
using namespace std;
ifstream f("sequencequery.in");
ofstream g("sequencequery.out");
long v[100001],n,i,smax,s,poz,st,dr,t,x,y,m;
int main()
{smax=-LONG_MAX;
   f>>n>>m;
   for(i=1;i<=n;i++)
        f>>v[i];
   for(t=1;t<=m;t++)
   {f>>x>>y;
       s=0;smax=-LONG_MAX;
       for(i=x;i<=y;i++)
   {s+=v[i];
   if(s>smax){smax=s;}
      if(s<0){s=0;}
   }

  g<<smax<<'\n';}

    return 0;
}