//#include <iostream>
#include <fstream>

using namespace std;

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

int main() {
  long int n,m,x,y,s[100001],j,k,l;
  long long int smax,suma;
  in >> n >> m;
  for(int i=1;i<=n;i++) 
   in >> s[i] ;
  for(int i=1;i<=m;i++)
  {
    in >> x >> y;
    if(x==y) {out << s[x] << '\n';continue;}
    else{
    suma = 0;
    smax = -100000 * (y-x+1) ;
    j = k = x;
   while(j!=y || k!=y)
   {
     for(l=j;l<=k;l++)
      suma+=s[l];
     if(suma>smax) smax = suma;
     k++;
     suma = 0;
     if(k==y+1) j++, k = j;
   }
   out << smax << '\n' ;
  }
  }
  return 0;
}