type t=record
     x,y:real;
     end;

function dlina(x1,y1,x2,y2:real): real;
begin
 dlina:=sqrt( (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) );
end;


var n,i:integer; x,y,p,cos,r:real; mas:array[1..103] of t;
Begin
readln(n,r);
p:=0;
for i:=1 to n do begin
  readln(mas[i].x,mas[i].y);
  if i>1 then p:=p+dlina(mas[i-1].x,mas[i-1].y,mas[i].x,mas[i].y);
end;
p:=p+dlina(mas[1].x,mas[1].y,mas[n].x,mas[n].y);



p:=p+2*3.14159*r;
writeln(p:1:2);

end.

jajaja

good!

I don't know this: 2*3.14159*r

saves a lot of code! jajaja

2*3.14159*r = d*Pi

d*R - It means the length of circle