Jim and Rose love to play dominoes together. They have a double-twelve set of dominoes that contains 91 dominoes. Jim is going to build a nice custom storage box for them. His dominoes are professional size: 2 in x 1 in x 3/8 in. He is going to build the box in the shape of a rectangle that is 4.2 in x 6.2 in. How deep does the box need to be at minimum if it is going to be able to hold all 91 dominoes?