(defun solve () 
    (let* ((n (read)) (a 0) (ren-like (make-array n :initial-element 0)))
    (dotimes (i n)
        (dotimes (j n)
            (if (equal (read) 'NYANPASS) (setf (aref ren-like j) (1+ (aref ren-like j))))))
    (dotimes (i n)
        (if (= (- n 1) (aref ren-like i))
            (cond 
                ((= a 0) (setf a (+ i 1)))
                ((>= a 1) (setf a -1)))))
    (if (= a 0) (setf a -1))
    a))
;つかれたーーーーーーーーーーーーーーーーーーーーー
;文字列の読み込みってもっと簡単にならないんかーーーーーーーーーーーーーーーー

(defun main () (format t "~A~%" (solve)))

(main)