#include <fstream>

using namespace std;
ifstream f("sequencequery.in");
ofstream g("sequencequery.out");
int a[100001];
int main()
{
    int n,m,i,j,s,x,y;
    long long smax;
    f>>n>>m;
    for (i=1;i<=n;i++) f>>a[i];
    for (j=1;j<=m;j++)
    {
        s=0;smax=-1e10;
        f>>x>>y;
        for (i=x;i<=y;i++)
    {
        s+=a[i];
        if (s>smax) smax=s;
        if (s<0) s=0;
    }
    g<<smax<<'\n';
    }
    return 0;
}