(define (solve f0 f1 n)
    (define *memo* (make-hash-table))
    (define (f k)
        (if (hash-table-exists? *memo* k)
            (hash-table-get *memo* k)
            (cond
                ((= k 0) f0)
                ((= k 1) f1)
                (else
                    (hash-table-put! *memo* k (logxor (f (- k 1)) (f (- k 2))))
                    (hash-table-get *memo* k)))))
    (f n))

(print (apply solve (map string->number (string-split (read-line) #\space))))