s = [chr(i + ord('a')) for i in range(26)]
s.extend(['ab', 'cd', 'ef', 'gh', 'ij', 'kl'])

def gen(level, n):
    if n == 1:
        return 'uvw'
    elif n % 2 == 1:
        return s[level] + gen(level + 1, n - 1) + s[level]
    cnt = 0
    while n % 2 == 0:
        n //= 2
        cnt += 1
    u = s[level] * cnt
    if n == 1:
        return u + 'uvw' + u
    else:
        return u + gen(level + 1, n - 1) + u

print(gen(0, int(input())))