import itertools
from math import isqrt

N = int(input())

ans = ''

sqN = isqrt(N)
it_ab = itertools.cycle('ab')
for _ in range(sqN * 2 - 1):
    ans += next(it_ab)
N -= sqN ** 2

sqN = isqrt(N)
it_cd = itertools.cycle('cd')
for _ in range(sqN * 2 - 1):
    ans += next(it_cd)
N -= sqN ** 2

it_xyz = itertools.cycle('xyz')
for _ in range(N):
    ans += next(it_xyz)

print(ans)