Text in the value field of an excel Pivot table

I have a excel spreadsheet with exam results in.  I need to pivot the table to get the results in a different format.  The pivot table will not keep the exam grade but inserts a number instead.  Is there a way to get it to keep the text?  I have found a solution online but you can only have 3 different text values.

This is a simplified example of what I have ..

Pupil      Subject    Grade

Boy 1       Maths       A 

Boy 1       Physics     B

Boy 1      Chemistry  C

Boy 2      Maths        AB

Boy 2      Physics      B

Boy2       Chemistry  D

and this is what I need....

Pupil       Maths      Physics     Chemistry

Boy 1        A              B                C

Boy 2       AB             B                D

Any suggestions gratefully received.

and what I need:

  I may be being dense, please humour if I am!