> type
>   node=record
>     maxl,maxr,maxm,l,r:longint;
>     same:boolean;
>   end;
> var
>   tree:array [0..400000] of node;
>   a:array [0..100001] of longint;
>   n,m:longint;
> procedure init;
> var
>   i:longint;
> begin
>   read(n); if n=0 then halt; readln(m);
>   for i:=1 to n do read(a[i]); readln;
> end;
> function max(x,y:longint):longint;
> begin
>   if x>y then exit(x) else exit(y);
> end;
> procedure updata(var t:node; lt,rt:node);
> begin
>   t.same:=lt.same and rt.same;
>   if lt.l<>rt.l then t.same:=false;
>   if lt.same and (lt.r=rt.l) then t.maxl:=lt.maxl+rt.maxl else t.maxl:=lt.maxl;
>   if rt.same and (rt.l=lt.r) then t.maxr:=rt.maxr+lt.maxr else t.maxr:=rt.maxr;
>   t.maxm:=max(lt.maxm,rt.maxm); if lt.r=rt.l then t.maxm:=max(t.maxm,lt.maxr+rt.maxl);
>   t.l:=lt.l; t.r:=rt.r;
> end;
> procedure buildtree(p,x,y:longint);
> begin
>   if x=y then
>   begin
>     tree[p].maxl:=1;
>     tree[p].maxr:=1;
>     tree[p].maxm:=1;
>     tree[p].l:=a[x];
>     tree[p].r:=a[x];
>     tree[p].same:=true;
>     exit;
>   end;
>   buildtree(p*2,x,(x+y) div 2);
>   buildtree(p*2+1,(x+y) div 2+1,y);
>   updata(tree[p],tree[p*2],tree[p*2+1]);
> end;
> function ask(p,x,y,xx,yy:longint):node;
> var
>   mid:longint; t,lt,rt:node;
> begin
>   if (x=xx) and (y=yy) then exit(tree[p]);
>   mid:=(x+y) div 2;
>   if yy<=mid then exit(ask(p*2,x,mid,xx,yy))
>   else if xx>mid then exit(ask(p*2+1,mid+1,y,xx,yy))
>   else
>   begin
>     lt:=ask(p*2,x,mid,xx,mid);
>     rt:=ask(p*2+1,mid+1,y,mid+1,yy);
>     updata(t,lt,rt); exit(t);
>   end;
> end;
> procedure main;
> var
>   i,x,y:longint; t:node;
> begin
>   for i:=1 to m do
>   begin
>     readln(x,y);
>     t:=ask(1,1,n,x,y);
>     writeln(t.maxm);
>   end;
> end;
> begin
>   while true do
>   begin
>     init;
>     buildtree(1,1,n);
>     main;
>   end;
> end.