import sys
sys.setrecursionlimit(10**9)
l = []
def calc3(s, N):
    if len(s) == N:
        print(s)
        l.append(s)
        return
    if len(s) > 0:
        c = s[-1]
        s2 = s[:]
        z = ord(c) - ord('a') + 2
        for i in range(z):
            st = s[:]
            st += chr(ord('a')+i)
            calc3(st[:], N)
    else:
        c = 'a'
        s += chr(ord(c))
        calc3(s[:], N)
def main():
    N = int(input())
    s = ''
    calc3(s[:], N)
main()
