In Lisp programming language.

Make a function pref which tells the number of times the first item in a list repeats.

Note: Do not have to use COUNT function.

I have provided the code with using the function count but you have to make function without using COUNT function.

this is some output of the function.

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code using COUNT.

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(defun pref(list) (count (nth 0 list) list) )

1sp>(pref '(a a a b b ccccc)). isp> (pref '(a b c d)) lsp>(pref '())