#include <fstream>
#include <vector>
using namespace std;
ifstream cin ("sequencequery.in");
ofstream cout ("sequencequery.out");
int v[100001],n,q;
int main()
{
    cin>>n>>q;
    for(int i=1; i<=n; i++) cin>>v[i];
    while(q--)
    {
        int p1,p2;
        cin>>p1>>p2;
        int sum=0,ans=-2e11;
        for(int i=p1;i<=p2;i++)
        {
            sum=max(sum,0)+v[i];
            ans=max(ans,sum);
        }
        cout<<ans<<'\n';
    }
}