from math import sqrt, floor

N = input()
ans = []
while N > 0:
    x = int(floor(sqrt(N)))
    ans.append(x)
    N -= x * x


def to_iwi(n, idx):
    c0 = chr(idx + ord('a'))
    c1 = chr(idx + ord('a') + 1)
    res = [c0]
    for i in xrange(n):
        res.append(c1)
        res.append(c0)
    return ''.join(res)

ans = [to_iwi(ans[i]-1, (i % 13)*2) for i in xrange(len(ans))]
print(''.join(ans))