import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
def f(x):
  ret=""
  while x>0:
    ret+=chr(97+x%10)
    x//=10
  return ret
for i in range(n-1):
  print("a"+f(i+1)+"a")
print("a"+f(n)+"n")