066536 / 957

program task957;
uses
Crt,Graph;
var
grDriver,grMode,ErrCode,i:integer;
j,n:longint;
begin
grDriver:=Detect;
InitGraph(grDriver, grMode, ''); {Ё­ЁжЁ «Ё§ жЁп Ја дЁЄЁ}
ErrCode:=GraphResult;
if ErrCode = grOk then begin
n:=10000000;
while i<600 do begin
setcolor(black);
circle(300,i,1);
inc(i);
setcolor(white);
circle(300,i,1);
for j:=1 to n do begin
end;
if n>30000 then
dec(n,30000);
end;
CloseGraph;
end
else WriteLn('ЋиЁЎЄ  Ё­ЁжЁ «Ё§ жЁЁ Ја дЁЄЁ:', GraphErrorMsg(ErrCode));
end.