from itertools import product
A = [chr(i) for i in range(97,123)]
A.remove("n")
C = {}
for a in A:
    C[a] = []
    for z in product(A,repeat=3):
        if a!=z[-1]:
            C[a].append(a+"".join(z))
N = int(input())
cnt = 0
x = "a"
while cnt<N-1:
    y = C[x].pop()
    print(y)
    cnt += 1
    x = y[-1]
print(x+"n")