It's seem not hard. But I always get WA.

type point=record
              x,y:real;
           end;
var p1,p2,p3:point;
    r,kc:real;
    i,n:integer;

begin
   readln(n,r);
   if n=1 then
   begin
      writeln(2*r*pi:0:2);
   end
   else
   if n=2 then
   begin
      readln(p1.x,p1.y);
      readln(p2.x,p2.y);
      kc:=sqrt(sqr(p1.x-p2.x)+sqr(p1.y-p2.y));
      writeln((2*r*pi+kc*2):0:2);
   end
   else
   begin
      readln(p1.x,p1.y);
      p2:=p1;
      for i:=2 to n do
      begin
         readln(p3.x,p3.y);
         kc:=kc+sqrt(sqr(p3.x-p2.x)+sqr(p3.y-p2.y));
         p2:=p3;
      end;
      kc:=kc+sqrt(sqr(p1.x-p3.x)+sqr(p1.y-p3.y));

      kc:=kc+(n-2)*r*pi;
      writeln(kc:0:2);
   end;
end.

> It's seem not hard. But I always get WA.
>
> type point=record
>               x,y:real;
>            end;
> var p1,p2,p3:point;
>     r,kc:real;
>     i,n:integer;
>
> begin
>    readln(n,r);
>    if n=1 then
>    begin
>       writeln(2*r*pi:0:2);
>    end
>    else
>    if n=2 then
>    begin
>       readln(p1.x,p1.y);
>       readln(p2.x,p2.y);
>       kc:=sqrt(sqr(p1.x-p2.x)+sqr(p1.y-p2.y));
>       writeln((2*r*pi+kc*2):0:2);
>    end
>    else
>    begin
>       readln(p1.x,p1.y);
>       p2:=p1;
>       for i:=2 to n do
>       begin
>          readln(p3.x,p3.y);
>          kc:=kc+sqrt(sqr(p3.x-p2.x)+sqr(p3.y-p2.y));
>          p2:=p3;
>       end;
>       kc:=kc+sqrt(sqr(p1.x-p3.x)+sqr(p1.y-p3.y));
>
>       kc:=kc+(n-2)*r*pi;  ---> Kc := Kc + 2*r*pi;     { ********}
>       writeln(kc:0:2);
>    end;
> end.

Dear Meoden! I give you solution of this simple program and you give
me solution of 1118! (aidar@ufa.ru)

var
  r, P : extended;
  a : array [1..101] of record
    x, y : extended;
  end;
  n, i : byte;


begin
  ReadLn (n, r);
  for i := 1 to n do with a [i] do ReadLn (x, y);
  with a [n + 1] do begin
    x := a [1].x;
    y := a [1].y;
  end;
  P := 2 * pi * r;
  for i := 1 to n do
    P := P +
      sqrt (sqr (a [i + 1].x - a [i].x) + sqr (a [i + 1].y - a
[i].y));
  WriteLn (P:0:2);
end.

Thanks Aidar
Very Nice
I see you have solved 1118 already
which one can i help you?
Thanks
Aidin_n7@hotmail.com