def main():
    N = int(input())
    students = set()
    cheeters = set()
    others = []
    for i in range(N):
        A, B = input().split()
        cheeters.add(A)
        others.append(B)
        students.add(A)
        students.add(B)

    honests = students ^ cheeters
    ans = []
    for name in others:
        if name in honests:
            if not name in ans:
                ans.append(name)

    for a in ans:
        print(a)
    

    
    


if __name__ == "__main__":
    main()