key = 'abcdefghijklmnopqrstuvwxyz'
s = []
for l in range(1, 10):
    for i in range(0, 26 - l, l):
        s.append(key[i: i + l])
        assert len(s[-1]) > 0
def gen(level, n):
    if n == 1:
        return s[level]
    elif n == 2:
        return s[level] + s[level]
    elif n % 2 == 0:
        u = s[level] * 2
        return u + gen(level + 1, n // 2 - 1) + u
    else:
        return s[level] + gen(level + 1, n - 1) + s[level]

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