program Project1;
var x1,x2,y1,y2,x3,y3:integer;a,b,c,p:real;f:text;
procedure line(x,x0,y,y0:real;var l:real);
begin
L:=sqrt(sqr(x-x0)+sqr(x-x0));
end;
begin
assign(f,'input.dat');reset(f);
readln(f,x1,y1,x2,y2,x3,y3);close(f);
assign(f,'output.sol');rewrite(f);
line(x1,y1,x2,y2,a);
line(x2,y2,x3,y3,b);
line(x3,y3,x1,y1,c);
p:=a+b+c;
write(f,p:0:2);close(f);
end.