My answer ----
<Professor> <First_Name>Alex</First_Name> <Middle_Initial>S.</Middle_Initial> <Last_Name>Aiken</Last_Name> </Professor> <Professor> <First_Name>William</First_Name> <Middle_Initial>J.</Middle_Initial> <Last_Name>Dally</Last_Name> </Professor> <Professor> <First_Name>Mark</First_Name> <Middle_Initial>A.</Middle_Initial> <Last_Name>Horowitz</Last_Name> </Professor> <Professor> <First_Name>Dan</First_Name> <Last_Name>Jurafsky</Last_Name> </Professor> <Professor> <First_Name>Dan</First_Name> <Last_Name>Jurafsky</Last_Name> </Professor> <Professor> <First_Name>Daphne</First_Name> <Last_Name>Koller</Last_Name> </Professor> <Professor> <First_Name>Beth</First_Name> <Last_Name>Levin</Last_Name> </Professor> <Professor> <First_Name>Subhasish</First_Name> <Last_Name>Mitra</Last_Name> </Professor> <Professor> <First_Name>Andrew</First_Name> <Last_Name>Ng</Last_Name> </Professor> <Professor> <First_Name>Andrew</First_Name> <Last_Name>Ng</Last_Name> </Professor> <Professor> <First_Name>Oyekunle</First_Name> <Last_Name>Olukotun</Last_Name> </Professor> <Professor> <First_Name>Eric</First_Name> <Last_Name>Roberts</Last_Name> </Professor> <Professor> <First_Name>Eric</First_Name> <Last_Name>Roberts</Last_Name> </Professor> <Professor> <First_Name>Mehran</First_Name> <Last_Name>Sahami</Last_Name> </Professor> <Professor> <First_Name>Mehran</First_Name> <Last_Name>Sahami</Last_Name> </Professor> <Professor> <First_Name>Sebastian</First_Name> <Last_Name>Thrun</Last_Name> </Professor> <Professor> <First_Name>Jennifer</First_Name> <Last_Name>Widom</Last_Name> </Professor> <Professor> <First_Name>Jennifer</First_Name> <Last_Name>Widom</Last_Name> </Professor>




Correct ans ---
<Professor> <First_Name>Alex</First_Name> <Middle_Initial>S.</Middle_Initial> <Last_Name>Aiken</Last_Name> </Professor> <Professor> <First_Name>William</First_Name> <Middle_Initial>J.</Middle_Initial> <Last_Name>Dally</Last_Name> </Professor> <Professor> <First_Name>Mark</First_Name> <Middle_Initial>A.</Middle_Initial> <Last_Name>Horowitz</Last_Name> </Professor> <Professor> <First_Name>Dan</First_Name> <Last_Name>Jurafsky</Last_Name> </Professor> <Professor> <First_Name>Dan</First_Name> <Last_Name>Jurafsky</Last_Name> </Professor> <Professor> <First_Name>Daphne</First_Name> <Last_Name>Koller</Last_Name> </Professor> <Professor> <First_Name>Beth</First_Name> <Last_Name>Levin</Last_Name> </Professor> <Professor> <First_Name>Subhasish</First_Name> <Last_Name>Mitra</Last_Name> </Professor> <Professor> <First_Name>Andrew</First_Name> <Last_Name>Ng</Last_Name> </Professor> <Professor> <First_Name>Andrew</First_Name> <Last_Name>Ng</Last_Name> </Professor> <Professor> <First_Name>Oyekunle</First_Name> <Last_Name>Olukotun</Last_Name> </Professor> <Professor> <First_Name>Eric</First_Name> <Last_Name>Roberts</Last_Name> </Professor> <Professor> <First_Name>Eric</First_Name> <Last_Name>Roberts</Last_Name> </Professor> <Professor> <First_Name>Mehran</First_Name> <Last_Name>Sahami</Last_Name> </Professor> <Professor> <First_Name>Mehran</First_Name> <Last_Name>Sahami</Last_Name> </Professor> <Professor> <First_Name>Sebastian</First_Name> <Last_Name>Thrun</Last_Name> </Professor> <Professor> <First_Name>Jennifer</First_Name> <Last_Name>Widom</Last_Name> </Professor> <Professor> <First_Name>Jennifer</First_Name> <Last_Name>Widom</Last_Name> </Professor>




Have to compare to find out differences