var
  x,y : array [1..100] of real;
  x1,x2,x3,y1,y2,y3,sum,d1,d2,d3,min : real;
  i,n : longint;
begin
  for i:=1 to 3 do
    readln(x[i],y[i]);
  min:=0;
  for i:=2 to 3 do
    if sqrt(sqr(x[1]-x[i])+sqr(y[1]-y[i]))<min then
      min:=sqrt(sqr(x[1]-x[i])+sqr(y[1]-y[i]));
  writeln(min:0:2);
end.