(let* ((p (string->number (read-line)))
       (n (string->number (read-line)))
       (r (let loop ((i 1)
                     (r p))
                    (if (> i n)
                        r
                        (let* ((l (map string->number (string-split (read-line) " ")))
                               (a (car l))
                               (b (cadr l))) 
                              (loop (+ i 1)
                                    (cond ((= r a) b)
                                          ((= r b) a)
                                          (else r))))))))
      (print r))