from functools import cmp_to_key

n = int(input())


def sorting_method(a, b):
    if ord(a[0]) > ord(b[0]):
        return 1
    elif ord(a[0]) < ord(b[0]):
        return -1
    elif ord(a[1]) > ord(b[1]):
        return 1
    elif ord(a[1]) < ord(b[1]):
        return -1
    return 0


while n:
    names = sorted([input() for _ in range(n)], key=cmp_to_key(sorting_method))
    for name in names:
        print(name)
    print()
    n = int(input())