import java.math.BigInteger;
public class Fact
{
    public static BigInteger factorial(int n)
    {
        if(n < 0)
        {
            throw new IllegalArgumentException();
        }
        if(n == 0 || n == 1)
        {
            return BigInteger.ONE;
        }
        return BigInteger.valueOf(n).multiply(factorial(n - 1));
    }
    /* this is javas answer to Python's starguments  */
    public static int atom(int... nums)
    {
        int out = 0;
        /*for(int k: nums)
        {
            out += k;
        }*/
        for(int  k = 0; k < 4; k++)
        {
            out += nums[k]
        }
        return out;
    }
    public static void main(String[] args)
    {
        System.out.println(factorial(100));
        System.out.println(factorial(3));
        //System.out.println(factorial(-3));
        System.out.println(atom(1,2,3,4,5));
        System.out.println(atom());
    }

}