program Factorial;
var n:integer;
function Factor(n:integer):real;
var v:real;
Begin if n in [0,1] then Factor:= 1 else Factor:= n*Factor(2*n-1);
end;
begin Write('Ââåäèòå ÷èñëî(0..33): ');
Readln(n);
Write('Ôàêòîðèàë ýòîãî ÷èñëà ðàâåí: ', Factor(n):11:0);
Readln;
End.