program Lab6;

{$APPTYPE CONSOLE}

uses
  SysUtils, Math;
var
  Multiply: double = 1;
  IsPrime: boolean;
  Count: integer;
  i: integer = 1;
  j: integer;
  Number: integer = 3;
  AbsAc: double;
  RelAc: double;
const
  C: double = 0.660161181584686;

begin
  Write(' Enter count prime numbers: ');
  Readln(Count);
  while i <= Count do
  begin
    IsPrime := true;
    for j:= 2 to Trunc(sqrt(Number)) do
      if (Number mod j) = 0 then
        IsPrime := false;
  if IsPrime = true then
  begin
    Multiply:= Multiply * (1-(1/IntPower(Number - 1, 2)));
    Inc(i);
  end;
  Inc(Number);
  end;
  AbsAc:= Abs(C - Multiply);
  RelAc:= AbsAc/C*100;
  Writeln(' Const C = ', C:15:15);
  Writeln(' Approximation = ', Multiply:15:15);
  Write(' Absolute accuracy = ', AbsAc:15:15); Writeln(', Relative accuracy = ', RelAc:15:15, '% .');


  Readln;
end.