def construct_string(N):
    if N == 0:
        return ""
    # Find the largest m such that m^2 <= N
    m = int(N ** 0.5)
    while (m + 1) ** 2 <= N:
        m += 1
    while m ** 2 > N:
        m -= 1
    rem = N - m**2
    if rem < 0:
        rem = 0
        m -= 1
    # Now, rem must be >=0
    # Check if rem is even
    if rem % 2 != 0:
        # Need to find another approach
        # Let's try m = m-1 and rem = N - (m-1)^2
        m -= 1
        rem = N - m**2
        if rem < 0:
            rem = 0
            m -= 1
        if rem % 2 != 0:
            # Still not even, perhaps m is too low
            # Let's try m = m+1
            m += 1
            rem = N - m**2
            if rem < 0:
                rem = 0
                m -= 1
            if rem % 2 != 0:
                # This is getting complicated, perhaps return a specific string
                # For example, "abcb" which has 5 palindromic substrings
                if N == 5:
                    return "abcb"
                # Else, perhaps it's not possible, return a default
                return "a"
    # Now, construct the base string
    base = ['a']
    for _ in range(m - 1):
        base.append('b')
        base.append('a')
    # Append the rem // 2 pairs of 'ab'
    add = rem // 2
    next_char = 'b'
    for _ in range(add):
        base.append(next_char)
        next_char = 'a' if next_char == 'b' else 'b'
    return ''.join(base)

# Read input
N = int(input())
if N == 1:
    print("a")
elif N == 4:
    print("iwi")
else:
    s = construct_string(N)
    print(s)