ABC problem

You are given a set of ABC blocks. Just like the ones you had when you were a kid. There are twenty blocks with two letters on each block. You are guaranteed to have a complete alphabet amongst all sides of the blocks. The sample blocks are:

ABC problem is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

((B O)

(X K)

(D Q)

(C P)

(N A)

(G T)

(R E)

(T G)

(Q D)

(F S)

(J W)

(H U)

(V I)

(A N)

(O B)

(E R)

(F S)

(L Y)

(P C)

(Z M))

The goal of this task is to write a function that takes a string and can determine whether you can spell the word with the given set of blocks. The rules are simple:

1. Once a letter on a block is used that block cannot be used again
2. The function should be case-insensitive

Example

<lang python>

   >>> can_make_word("")
   False
   >>> can_make_word("a")
   True
   >>> can_make_word("bark")
   True
   >>> can_make_word("book")
   False
   >>> can_make_word("treat")
   True
   >>> can_make_word("common")
   False
   >>> can_make_word("squad")
   True

</lang>