uses crt,graph;
const
        h=0.01;
        scale=100;
var GrDr,GrM,CX,CY:integer;
    a,b,x,y:real;
begin
        GrDr:=9;
        GrM:=2;
        initgraph(GrDr,GrM,'');

        CX:=round(GetMaxX/2);
        CY:=round(GetMaxY/2);

        moveto(CX-scale*2,CY);
        linerel(scale*2,-scale*2);
        linerel(scale*2,scale*2);
        linerel(-scale*2,scale*2);
        linerel(-scale*2,-scale*2);
        circle(CX,CY,scale*2);
        x:=-2;
        y:=-2;
        repeat
           repeat
           a:=2*(abs(x)+abs(y));
           b:=sqr(x)+sqr(y);
           if (a>=b) and (b>=4) then
                putpixel(CX+round(x*scale),CY+round(y*scale),15);
           x:=x+h;
           until x>2;
        y:=y+h;
        until y>2;
        readln;
        closegraph;
end.