import java.math.BigInteger;

class Main {
//Stepik code: start

    /**
     * Calculates factorial of given <code>value</code>.
     *
     * @param value positive number
     * @return factorial of <code>value</code>
     */
    public static BigInteger factorial(int value) {
        return BigInteger.ZERO; // your implementation here
    }
//Stepik code: end
}
