#include <iostream>

using namespace std;
int v[100001];
int searchmaxx(int x,int y)
{
    int i,maxx=0,s=0;
    for(i=x;i<=y;i++)
    {
        s+=v[i];
        if(s>maxx) maxx=s;
        if(s<0)
        {
            s=0;
        }
    }
    return s;
}
int main()
{
    int n,i,x,k,a,y;
    cin>>n>>k;
    for(i=1;i<=n;i++)
    {
        cin>>v[i];
    }
    for(a=1;a<=k;a++)
    {
        cin>>x>>y;
        cout<<searchmaxx(x,y)<<"\n";
    }
    return 0;
}