> #include<stdio.h>
> 
> #define N 100010
> 
> struct NODE{
> 	int b,e,l,r;
> 	int number, last ;
> } node[N*4+1] ;
> 
> int len,data[N];
> 
> int build(int a,int b)
> {
> 	int temp=len , mid=(a+b)/2 ;
> 	node[temp].b=a , node[temp].e=b ;
> 	len++;
> 	if(a==b)
> 	{
> 		node[temp].number=1;
> 		node[temp].last=1;
> //		node[temp].l=node[temp].r
> 		return temp;
> 	}
> 	node[temp].l=build(a,mid);
> 	node[temp].r=build(mid+1,b);
> 	int left_c=node[temp].l , right_c=node[temp].r , p , lcount =0 ,rcount=0 , rec , max=0 ;
> 	rec=data[mid];
> 	p=mid;
> 	while(p>=a&&data[p]==rec) { p-- , lcount++; }
> 	node[left_c].last=lcount;
> 	rec=data[mid+1];
> 	p=mid+1;
> 	while(p<=b&&data[p]==rec) { p++ , rcount++; }
> 	node[right_c].last=rcount;
> 	if(data[mid]==data[mid+1])
> 	{
> 		max=lcount+rcount;
> 	}
> 	if(node[left_c].number>max) max=node[left_c].number;
> 	if(node[right_c].number>max) max=node[right_c].number;
> 	node[temp].number=max;
> 	return temp;
> }
> 
> int query(int index , int a , int b)
> {
> 	int begin=node[index].b , end=node[index].e , mid = (begin+end) / 2 ;
> 	if(a==begin && b==end) 
> 		return node[index].number;
> 	if(a>mid) return query( node[index].r , a , b);
> 	if(b<mid+1) return query( node[index].l , a , b);
> 	int temp1,temp2,max;
> 	if(node[index].l>0)	temp1 = query( node[index].l , a , mid);
> 	if(node[index].r>0) temp2 = query( node[index].r , mid+1, b);
> 	max = temp1>temp2 ? temp1:temp2;
> 	if(data[mid]!=data[mid+1])
> 		return max;
> 	temp1= node[node[index].l].last > (mid-a+1) ? (mid-a+1) : node[node[index].l].last ;
> 	temp2= node[node[index].r].last > (b-mid) ? (b-mid) : node[node[index].r].last ;
> 	if(max<temp1+temp2) max=temp1+temp2;
> 	return max;
> }
> 
> int main()
> {
> 	int i,n,q,a,b;
> 	while(scanf("%d",&n)==1 && n)
> 	{
> 		scanf("%d",&q);
> 		for(i=0;i<n;i++) scanf("%d",&data[i]);
> 		build(0,n-1);
> 		while(q--)
> 		{
> 			scanf("%d%d",&a,&b);
> 			printf("%d\n", query(0,a-1,b-1));
> 		}
> 	}
> 	return 0;
> }