# -*- coding: utf-8 -*-

def main():

    N = int(input())
    M = int(input())
    res = N
    for i in range(M):
        l, r = map(int, input().split())
        if res == l:
            res = r
        elif res == r:
            res = l

    print(str(res) + "\n")
if __name__ == '__main__':
    main()