def foo(n):
    def bar():
        alph = [_ for _ in 'abcdefghijklmopqrstuvwxyz']
        i = 0
        for _1 in alph:
            for _2 in alph:
                for _3 in alph:
                    for _4 in alph:
                        i += 1
                        yield first+_1+_2+_3+('n' if i==n else _4)
    first = 'a'
    for i,word in enumerate(bar()):
        if i == n:
            break
        print(word)
        first = word[-1]

if __name__ == '__main__':
    foo(int(input()))