import math
N=int(raw_input())

ans=""
charset=["ab","cd"]
ind=[0,0]
setInd=0

while N>0:
    a=int(math.sqrt(N))
    if a*a+a>N:
        for i in range(2*a-1):
            ans+=charset[setInd][ind[setInd]]
            ind[setInd]=1-ind[setInd]
        N-=a*a
    else:
        for i in range(2*a):
            ans+=charset[setInd][ind[setInd]]
            ind[setInd]=1-ind[setInd]
        N-=a*a+a
    setInd=1-setInd
print ans