#include <cstdio>

using namespace std;
FILE *fin=fopen("sequencequery.in","r");
FILE *fout=fopen("sequencequery.out","w");
int a[100001],x,y,i,j,m,n,s,smax;
int main()
{
    fscanf (fin,"%d%d",&n,&m);
    for(i=1;i<=n;i++)
        {
        fscanf(fin,"%d",&a[i]);
        }
    for(i=1;i<=m;i++)
        {
        fscanf(fin,"%d%d",&x,&y);
        for(j=x;j<=y;j++)
        {s=s+a[j];
        if(s>smax){smax=s;}
        if(s<0){s=0;}
        }
        fprintf(fout,"%d\n",smax);
        smax=-2000000;s=0;
        }

    return 0;
}