#include <iostream>
#include <fstream>
using namespace std;
#define FOR(i,a,b)  for(int i=a; i<=b; i++)
ifstream f("sequencequery.in");
ofstream g("sequencequery.out");
long N, M, a[100005],x,y;
int main()
{
    f>>N>>M;
    FOR(i,1,N)f>>a[i];
    FOR(i,1,M)
    {
        f>>x>>y;
        long sum=0,maxi=-100000;
        FOR(j,x,y)
        {
            if(sum<0)
                sum=a[j];
            else
                sum+=a[j];
            if(sum>maxi)
                maxi=sum;
        }
        g<<maxi<<'\n';

    }
    f.close();g.close();
    return 0;
}