(use util.match) (define (main args) (print (let1 ls (string->list (read-line)) (let loop ([ls ls]) (match ls [(a b . c) (if (and (char-lower-case? a) (char=? b #\space)) (loop c) "No")] [(a) (if (char-lower-case? a) "Yes" "No")] [() "Yes"])))) 0)