#include <bits/stdc++.h>
using namespace std;
ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");
int sm,n,m,x,y,a[100005],b[100005];
int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++)
        fin>>a[i];
    for(int j=1;j<=m;j++)
    {
        sm=-10000000;
        fin>>x>>y;
        b[x-1]=0;
        for(int i=x;i<=y;i++)
        {
            b[i]=a[i];
            if (b[i-1]+a[i]>b[i])b[i]=b[i-1]+b[i];
            if(b[i]>sm)sm=b[i];
        }
        fout<<sm<<'\n';
    }
    return 0;
}