Statement

William is a fan of word-play, so of course he loves isograms! An isogram is a word or sentence with the peculiarity that the same letter is never used twice. For example, the word "isogram" itself is indeed an isogram, as well as the following sentence: "The Clunky Isogram". You can easily verify that no letter is ever re-used. Finding out if a sentence is an isogram is child's play, so William decided instead to look for quasi-isograms. We call a sentence "quasi-isogram" if it uses each letter at most twice. Of course, by this definition we can infer that any isogram is also a quasi-isogram. In order to test his quasi-isogram-identification skills, William created a list of N sentences. Help him by counting how many of these are quasi-isograms!