n=int(input())
c='A'
for i in range(n):

  for j in range(0,i+1):
    print(c,end="")
  c=chr(ord(c)+1)
  print()
  

/**************************************************************
	Problem: 1977
	User: admin
	Language: Python
	Result: Accepted
	Time:96 ms
	Memory:34244 kb
****************************************************************/