(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))