#include<stdio.h>  
  
#define X 100001  
  
int sum(lint x, int y, int a[])  
{  
 int i.s=0,sbest=-X;  
 for(i=x; i<=y; ++i)  
 {  
  if(s>=0) s+=a[i];  
      else s=a[i];  
  if(s>sbest) sbest=s;  
 }  
 return sbest;  
}  
  
int main()  
{  
 freopen("sequencequery.in","r",stdin);  
 freopen("sequencequery.out","w",stdout);  
 int x,y,a[X],n,m,i;  
 scanf("%d%d",&n,&m);  
 for(i=1; i<=n; ++i) scanf("%d",&a[i]);  
 for(; m; --m)  
 {  
  scanf("%d%d",&x,&y);  
  printf("%d\n",sum(x,y,a));  
 }  
 return 0;  
}