#include <iostream>
using namespace std;
int main () {
         int chislo;
         long double df=1;
         cout << "Vyvedete chisloto na koeto shte presmqtate dvoen faktoriel: "; cin >> chislo;
         cout << "Dvoen faktroriel na chisloto " << chislo << " e: ";
         do {
                  df = df *chislo;
                  chislo -= 2; }
         while(chislo>1);
                  cout << df ;
         system("pause");
         return 0;
}