explain the following example in simple terms

Show that the language L={anbl:n=l} is not regular. Here we need a bit of ingenuity to apply the pumping lemma directly. Choosing a string with n=l+1 or n=l+2 will not do, since our opponent can always choose a decomposition that will make it impossible to pump the string out of the language (that is, pump it so that it has an equal number of a 's and b 's). We must be more inventive. Let us take n=m! and l=(m+1)!. If the opponent now chooses a y (by necessity consisting of all a 's) of length k