def scan; gets.split.map(&:to_i); end

# abababa
def func(n)
    m = (n+2) / 2
    return (n.even? ? (m-2)*(m-1) : m*(m-1)-m+1) + n
end

n = gets.to_i
puts "🍣" if n <= 0
iwi = ['a','b']

p (1..8).map{|e| func(e)}

while n > 3

    # binary search
    c = nil
    l = 0; h = 100000
    while l < h
        c = (l+h+1)/2;
        if (n < func(c))
            h = c-1
        else
            l = c
        end
    end
    
    k = l
    n -= func(l)
    
    print ((iwi[0]+iwi[1])*((k)/2))
    print iwi[0] if k.odd?
    
    iwi.map!(&:succ!).map!(&:succ!)
end

print 'xyz'[0..(n-1)] if 0 < n