How can I will obtain the following output of this problem using C language?

Question

Given a table of the form:
Product    Sold on
A           1/1/1980
B           1/1/1980
C           1/1/1980
A           1/1/1980
B           1/1/1980
C           2/1/1980
A           2/1/1980

There are 30 products and 10,000 records of such type. Also the month period during which sales happened is given to u.

Write the program in c language to display the result as:

Product   Month      No. of copies
A           January       12
A           February     15
A           March         27
B           January      54
B           February     15
B           March         10
C           January        37