var x,y:array [0..2] of real;
 r0,r1,r2,r12,a,b,c,t:real;
 i:integer;
 
function dist (x1,y1,x2,y2:real):real; {Расстояние между точками}
begin
 dist:=sqrt(sqr(x2-x1)+sqr(y2-y1));
end;
 
begin
 
 readln (x[0],y[0],x[1],y[1],x[2],y[2]);
 
  r1:=dist(x[0],y[0],x[1],y[1]);
 r2:=dist(x[0],y[0],x[2],y[2]);
 r12:=dist(x[1],y[1],x[2],y[2]);
 
  a:=y[2]-y[1]; b:=x[1]-x[2]; c:=-x[1]*(y[2]-y[1])+y[1]*(x[2]-x[1]);
  t:=dist (a,b,0,0);
  if c>0 then begin a:=-a; b:=-b; c:=-c; end;
  r0:=(a*x[0]+b*y[0]+c)/t;
  write (abs(r0):6:2);
  
 
end.