#include <iostream>
#include <fstream>
using namespace std;
ifstream f ("sequencequery.in");
ofstream g ("sequencequery.out");
int n,m;
int vek[100005];
int main()
{
    f>>n>>m;
    for(int i=1;i<=n;++i)
    {
        f>>vek[i];
    }
    for(int i=1;i<=m;++i)
    {
        int x,y;
        f>>x>>y;
        int s=0;
        int sm=-100000;
        for(int j=x;j<=y;++j)
        {

            s+=vek[j];
            if(s>sm)
                sm=s;
            if(s<0)
            {
                s=0;
            }


        }
        g<<sm<<"\n";
    }
    return 0;
}