#include <iostream>
#include <fstream>
#define NMAX 100005
#define INF 200005
using namespace std;

ifstream in("sequencequery.in");
ofstream out("sequencequery.out");

int n,a[NMAX],m,x,y;
int best[NMAX];

int din(int x, int y)
{
    for(int i=0;i<=n;i++)
        best[i]=0;
    int Max =a[x];
    best[x] = a[x];
    for(int i=x+1;i<=y;i++)
    {
        best[i] = a[i];
        if(best[i] < best[i-1]+a[i])
            best[i] = best[i-1] + a[i];
        if(Max <best[i])
            Max = best[i];
    }
    return Max;
}


int main()
{
    in >> n >> m;
    for(int i=1;i<=n;i++)
        in >> a[i];
    for(int i=0;i<m;i++)
    {
        in >> x >> y;
        out << din(x,y) << "\n";
    }

    return 0;
}