> First i calculate the degree between wally house and every friend
by
> procedure ATG and then sort friends by their degree...
>
> Type
>   Point               =record
>     x,y,d             :real;
>     ID                :Integer;
>   end;
> Var
>   a                   :array[0..1000] of point;
>   n,i                 :integer;
>
> function partition(first,last:integer):integer;
> Var
>   t                   :point;
>   i,j                 :integer;
>   x                   :real;
> begin
>   i:=first-1;
>   j:=last+1;
>   x:=a[first].d;
>   while true do
>   begin
>     repeat inc(i);
>     until a[i].d<=x;
>     repeat dec(j);
>     until a[j].d>=x;
>     if i<j then begin
>       t:=a[i]; a[i]:=a[j]; a[j]:=t; end
>     else begin
>       partition:=j; exit; end;
>   end;
> end;
>
> Procedure qsort(first,last:integer);
> Var
>   w                   :integer;
> begin
>   if first<last then
>   begin
>     w:=partition(first,last);
>     qsort(first,w);
>     qsort(w+1,last);
>   end;
> end;
>
> Function ATG(x:integer):real;
> Var
>   dx,dy,k             :real;
> begin
>   dx:=a[x].x-a[0].x;
>   dy:=a[x].y-a[0].y;
>   if dx=0 then
>     k:=90
>   else
>     k:=arctan(dy/dx)/pi*180;
>   if (k<0) or ((k=0) and (dx<0)) then k:=k+180;
>   if dy<0 then k:=k+180;
>   atg:=k;
> end;
>
> begin
>   readln(a[0].x,a[0].y);
>   readln(n);
>   for i:=1 to n do
>   begin
>     readln(a[i].x,a[i].y,a[i].ID);
>     a[i].d:=ATG(i);
>   end;
>   qsort(1,n);
>   writeln(0);
>   for i:=1 to n do
>     writeln(a[i].Id);
>   writeln(0);
> end.
>