Ideia for 3 match puzzle like jewelMania [on hold]

I want to make 3 match puzzle game like jewelMania.

But i want to make a specific fuction.

board size is 7 * 7.

When starting game, user input a number and makea block field that contains available swap block(it means if you swap it, it will be removed) as many input number.

I'm thinking in this solution over 6 hour but still don't know how to make the program.