Question 1168624
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<pre>

(1)   {{{26^4}}}.   


      By the way, when you call it as "4-digit password using only the 26 letters from the alphabet"

      it is a kind of the nonsense. It is still a "4-letter password using only the 26 letters from the alphabet".


      Isn't it ?



(2)   They are what you can not distinct.



(3)     ?



(4)   {{{(75*74)/2}}}



(5)     ?
</pre>

Toooooooo many questions for one post.