Find difference between two custom list objects

public class Details
    {
        public String classNAme;
        public List<Student> studentCollection;
    }
    public class Student
    {
        public string Rollnumber, Name;
        public List<Marks> studentMarks;
    }
    public class Marks
    {
        public string Eng, Maths, Term;
    }

Old XML
----------
<Details>
                        <Class>1.0</Class>
                        <Student  RollNumber="001" Name="Aaa">
                                <Marks Eng="50" Maths="50" Term="First"/>
                                <Marks Eng="60" Maths="57" Term="Second"/>
                                <Marks Eng="55" Maths="56" Term="Third"/>
                                <Marks Eng="59" Maths="85" Term="Fourth"/>
                        </Student>
                        <Student  RollNumber="002" Name="Baa">
                                ....
                        </Student>
</Details>
New XML
----------
<Details>
                        <Class>1.0</Class>
                        <Student  RollNumber="001" Name="Aaa">
                                <Marks Eng="50" Maths="60" Term="First"/>
                                <Marks Eng="60" Maths="57" Term="Second"/>
                                <Marks Eng="55" Maths="46" Term="Third"/>
                                <Marks Eng="59" Maths="85" Term="Fourth"/>
                        </Student>
                        <Student  RollNumber="002" Name="Baa">
                                ....
                        </Student>
</Details>
 
HI All, Using XELement.Load I have loaded the xml into the above class. My class  and XML structure are given above.
I have a requirement where I have  to compare two xml files. In hte new XML, Marks for a student(s) might change for a particular term(s). 
I need to identify the student and the term for which eth marks has been chnaged.
can u plz let me knwo how to get the difference between tow list<Marks> object.
I would be holding hte object like,
Details oldDetails = GetDetails(path1);
Details newDetails = GetDetails(path2);
Thanks,