; 文字列の比較を行う
; position 関数を使うか mismatch 関数を使う
(defun main (&rest argv)
  (declare (ignorable argv))
  (write-char (aref "yukicoder" (position #\? (read-line))))
  ; (write-char (aref "yukicoder" (mismatch "yukicoder" (read-line))))
  (terpri))
(main)