class Bit {

    int bit;

    void setBit(int bit) {
	if (bit < 0 || bit > 1)
	    throw new IllegalArgumentException("bit must be either 0 or 1");
	this.bit = bit;
    }

    public static void main (String[] args) {
	Bit bit = new Bit();
	bit.setBit(4);
    }
}