How can I get the last value entered from a set of selected cells in Excel?

I have to get the last value entered in a set of selected cells in Excel. For Eg: In an Excel sheet in Column A I will enter the names of the students. In Column B, C, D, & E I will enter the Grades (say A,B,C & D)awarded to the student in each event. In the last Column F, I want to retu the Grade which has got for his last event. Say there are 4 events. Student-1 has participated in all the 4 events and I will enter the Grades against each event and in the last column I want to display the Grade achieved by the Student-1 in the last event. Student-2 only participated in 2 events, so I will the Grades against those events. In the last column I want to display the Grade achieved by the Student in his last event out of the 2 which he participated.