private void setup(String expression) {
		// if there are parentheses around the entire expression, and the entire expression is negated
		if(encased(expression) && expression.startsWith(NEGATIVE+"")) {
			negative = true;						// make the node negative
			expression = expression.substring(1);	// remove the negative sign
			expression = trim(expression);			// trim the useless parentheses
		}
		// if there is a logical operator in there, parse the arguments
		if(	expression.contains(AND + "") || expression.contains(OR + "") || expression.contains(IMPLY + "")) {
			expression = trim(expression);
			findMiddle(expression);
		} else {	// its a leaf, meaning its an argument itself
			negative = expression.startsWith(NEGATIVE+"");
			root = expression.replace(NEGATIVE + "", "");
			left = null;
			right = null;
		}
	}