from string import ascii_lowercase

N = input()
S = ''
p = 0
alp = ascii_lowercase[2:]

while N > 0:
    if N > 3:
        N -= 1
        S += 'a'
        i = 3
        while i <= N:
            S += 'ba'
            N -= i
            i += 2
    if N > 0:
        S += alp[p]
        p = (p + 1) % 24
        N -= 1
        
print S